CVE-2025-49630

In certain proxy configurations, a denial of service attack against Apache HTTP Server versions 2.4.26 through to 2.4.63 can be triggered by untrusted clients causing an assertion in mod_proxy_http2.

Configurations affected are a reverse proxy is configured for an HTTP/2 backend, with ProxyPreserveHost set to "on".

In certain proxy configurations, a denial of service attack against Apache HTTP Server versions 2.4.26 through to 2.4.63 can be triggered by untrusted clients causing an assertion in mod_proxy_http2. Configurations affected are a reverse proxy is configured for an HTTP/2 backend, with ProxyPreserveHost set to "on".

The mod_h2 Apache httpd module implements the HTTP2 protocol (h2+h2c) on top of libnghttp2 for httpd 2.4 servers.

Security Fix(es):

A vulnerability classified as problematic has been found in Apache HTTP Server up to 2.4.63 (Web Server).CWE is classifying the issue as CWE-617. The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.This is going to have an impact on availability.Upgrading to version 2.4.64 eliminates this vulnerability.The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2025-21017).(CVE-2025-49630)

The mod_h2 Apache httpd module implements the HTTP2 protocol (h2+h2c) on top of libnghttp2 for httpd 2.4 servers.

Security Fix(es):

• httpd: mod_proxy_http2: untrusted input from a client causes an assertion to fail in the Apache mod_proxy_http2 module (CVE-2025-49630)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

The mod_h2 Apache httpd module implements the HTTP2 protocol (h2+h2c) on top of libnghttp2 for httpd 2.4 servers.

Security Fix(es):

• httpd: mod_proxy_http2: untrusted input from a client causes an assertion to fail in the Apache mod_proxy_http2 module (CVE-2025-49630)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

The httpd packages provide the Apache HTTP Server, a powerful, efficient, and extensible web server.

Security Fix(es):

• httpd: insufficient escaping of user-supplied data in mod_ssl (CVE-2024-47252)

• httpd: mod_ssl: access control bypass by trusted clients is possible using TLS 1.3 session resumption (CVE-2025-23048)

• httpd: mod_proxy_http2: untrusted input from a client causes an assertion to fail in the Apache mod_proxy_http2 module (CVE-2025-49630)

• httpd: HTTP Session Hijack via a TLS upgrade (CVE-2025-49812)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

In certain proxy configurations, a denial of service attack against Apache HTTP Server versions 2.4.26 through to 2.4.63 can be triggered by untrusted clients causing an assertion in mod_proxy_http2. Configurations affected are a reverse proxy is configured for an HTTP/2 backend, with ProxyPreserveHost set to "on".

The mod_h2 Apache httpd module implements the HTTP2 protocol (h2+h2c) on top of libnghttp2 for httpd 2.4 servers.

Security Fix(es):

• httpd: mod_proxy_http2: untrusted input from a client causes an assertion to fail in the Apache mod_proxy_http2 module (CVE-2025-49630)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

The mod_h2 Apache httpd module implements the HTTP2 protocol (h2+h2c) on top of libnghttp2 for httpd 2.4 servers.

Security Fix(es):

• httpd: mod_proxy_http2: untrusted input from a client causes an assertion to fail in the Apache mod_proxy_http2 module (CVE-2025-49630)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

The httpd packages provide the Apache HTTP Server, a powerful, efficient, and extensible web server.

Security Fix(es):

• httpd: insufficient escaping of user-supplied data in mod_ssl (CVE-2024-47252)
• httpd: mod_ssl: access control bypass by trusted clients is possible using TLS 1.3 session resumption (CVE-2025-23048)
• httpd: mod_proxy_http2: untrusted input from a client causes an assertion to fail in the Apache mod_proxy_http2 module (CVE-2025-49630)
• httpd: HTTP Session Hijack via a TLS upgrade (CVE-2025-49812)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

In certain proxy configurations, a denial of service attack against Apache HTTP Server versions 2.4.26 through to 2.4.63 can be triggered by untrusted clients causing an assertion in mod_proxy_http2.

Configurations affected are a reverse proxy is configured for an HTTP/2 backend, with ProxyPreserveHost set to "on".

In certain proxy configurations, a denial of service attack against Apache HTTP Server versions 2.4.26 through to 2.4.63 can be triggered by untrusted clients causing an assertion in mod_proxy_http2.

Configurations affected are a reverse proxy is configured for an HTTP/2 backend, with ProxyPreserveHost set to "on".

In certain proxy configurations, a denial of service attack against Apache HTTP Server versions 2.4.26 through to 2.4.63 can be triggered by untrusted clients causing an assertion in mod_proxy_http2.

Configurations affected are a reverse proxy is configured for an HTTP/2 backend, with ProxyPreserveHost set to "on".

In certain proxy configurations, a denial of service attack against Apache HTTP Server versions 2.4.26 through to 2.4.63 can be triggered by untrusted clients causing an assertion in mod_proxy_http2.

Configurations affected are a reverse proxy is configured for an HTTP/2 backend, with ProxyPreserveHost set to "on".

In certain proxy configurations, a denial of service attack against Apache HTTP Server versions 2.4.26 through to 2.4.63 can be triggered by untrusted clients causing an assertion in mod_proxy_http2.

Configurations affected are a reverse proxy is configured for an HTTP/2 backend, with ProxyPreserveHost set to "on".

• SECURITY UPDATE: denial of service attack caused by untrusted clients triggering assertion in mod_proxy_http2
  • debian/patches/CVE-2025-49630.patch: tolerate missing host header in h2 proxy to fix issue with HTTP/0.9 request without Host header
  • CVE-2025-49630

• CVE-2025-49630: fix denial of service attack triggered by untrusted clients causing an assertion in mod_proxy_http2
• CVE-2025-23048: fix access control bypass by trusted clients in mod_ssl configurations
• CVE-2024-47252: escape user-supplied data in mod_ssl to prevent untrusted SSL/TLS clients from inserting escape characters into log file
• CVE-2025-49812: remove support for TLS upgrade to mitigate HTTP desynchronisation attack

• CVE-2025-49630: fix assertion caused by untrusted clients triggering denial of service attack in mod_proxy_http2
• CVE-2025-23048: fix access control bypass by trusted clients using TLS 1.3 session resumption
• CVE-2024-47252: escape user-supplied data to prevent log file injection in mod_ssl
• CVE-2025-49812: remove support for TLS upgrade to prevent HTTP desynchronisation attack

• CVE-2025-49630: fix denial of service attack triggered by untrusted clients causing an assertion in mod_proxy_http2
• CVE-2025-23048: fix access control bypass by trusted clients in mod_ssl configurations
• CVE-2025-49812: remove support for TLS upgrade to mitigate HTTP desynchronisation attack
• CVE-2024-47252: escape user-supplied data in mod_ssl to prevent untrusted SSL/TLS clients from inserting escape characters into log files

• CVE-2025-49630: prevent denial of service attack by fixing assertion issue in mod_proxy_http2

• SECURITY UPDATE: potential SSRF in mod_rewrite via RewriteRule substitutions that produce a scheme-like target
  • debian/patches/CVE-2024-39573.patch: add the previously stripped per-directory prefix, or an implicit '/' root prefix, to the substituted URI before the query args are split in apply_rewrite_rule() in modules/mappers/mod_rewrite.c; otherwise a rule such as "RewriteRule ^/some/path(.*) $1" turns "/some/pathscheme:..." into the fully qualified URL "scheme:...", which mod_proxy then handles. Upstream fix 93aec0e3ca451bcc97f6d91c14d5399d13a73365 (SVN r1918600).
  • CVE-2024-39573
• SECURITY UPDATE: insufficient escaping of mod_ssl variables written to the log by CustomLog
  • debian/patches/CVE-2024-47252.patch: pass the results of ssl_var_log_handler_c() and ssl_var_log_handler_x() through ap_escape_logitem() in modules/ssl/ssl_engine_vars.c, so an untrusted TLS client can no longer insert escape characters into log files through the %{varname}c and %{varname}x formats logging mod_ssl variables such as SSL_TLS_SNI. Upstream fix c01e60707048be14a510f0a92128a5227923215c (SVN r1927042).
  • CVE-2024-47252
• SECURITY UPDATE: access control bypass by trusted clients through TLS 1.3 session resumption in mod_ssl
  • debian/patches/CVE-2025-23048.patch: move the ssl_server_compatible() check in ssl_hook_ReadReq() in modules/ssl/ssl_engine_kernel.c out of the SNI-present branch, so the handshake virtual host and the request virtual host are compared even when the client sent no SNI, as happens on a resumed TLS 1.3 session; previously such a request could reach a virtual host with different client certificate restrictions when SSLStrictSNIVHostCheck was off. Upstream fix c4cfa50c9068e8b8134c530ab21674e77d1278a2 (SVN r1927043).
  • CVE-2025-23048
• SECURITY UPDATE: denial of service through an assertion failure in mod_proxy_http2
  • debian/patches/CVE-2025-49630.patch: fall back to the server hostname when ProxyPreserveHost is on but the incoming request carried no Host: header, in open_stream() in modules/http2/h2_proxy_session.c, instead of passing a NULL authority on to the HTTP/2 backend and tripping an assertion. Upstream fix 88304321841a2fe8bd5eacc70e69418b0b545ca5 (SVN r1927044).
  • CVE-2025-49630
• SECURITY UPDATE: query string passed by mod_cgid to Server Side Includes #exec cmd= commands
  • debian/patches/CVE-2025-58098.patch: pass NULL instead of r->args to create_argv() for SSI_REQ requests in cgid_server(), and tolerate a NULL args in create_argv(), in modules/generators/mod_cgid.c; otherwise the shell-escaped query string is appended as arguments to the command line of an SSI "#exec cmd=..." directive. Upstream fix ecc1b8f3817e3dcab9c1f24f905752d3c0a279af (SVN r1930161).
  • CVE-2025-58098
• SECURITY UPDATE: integer overflow in the mod_md ACME renewal backoff timer
  • debian/patches/CVE-2025-55753.patch: double the retry delay step by step with an overflow and cap check in md_job_delay_on_errors() in modules/md/md_status.c instead of shifting job->min_delay left by err_count-1 in one go; otherwise after roughly 30 days of consecutive renewal failures the shift wraps the signed apr_time_t, the backoff collapses to 0 and the server retries against the ACME CA in a tight loop. Upstream fix 20666cfb765b8ad14efa3d97bc92d344b9395c89 (SVN r1929515).
  • CVE-2025-55753

• SECURITY UPDATE: DoS in mod_proxy_http2 via missing Host header with ProxyPreserveHost
  • debian/patches/CVE-2025-49630.patch: in open_stream() in modules/http2/h2_proxy_session.c, when preserve_host is on and the client request has no Host header, fall back to r->server->server_hostname and add it to the request headers so a NULL authority no longer trips an assertion in the h2 proxy path. Backported from httpd commit 88304321841a2fe8bd5eacc70e69418b0b545ca5 (SVN r1927044, 2.4.x branch), plus adapted regression test from SVN r1934478 (test/modules/http2/test_600_h2proxy.py).
  • CVE-2025-49630

HTTP response splitting. (CVE-2024-42516) SSRF with mod_headers setting Content-Type header. (CVE-2024-43204) mod_ssl error log variable escaping. (CVE-2024-47252) mod_proxy_http2 denial of service. (CVE-2025-49630) mod_ssl access control bypass with session resumption. (CVE-2025-23048) mod_ssl TLS upgrade attack. (CVE-2025-49812) HTTP/2 DoS by Memory Increase. (CVE-2025-53020) 'RewriteCond expr' always evaluates to true in 2.4.64. (CVE-2025-54090) You will find the update delay sometimes causes a failure; just restart the service after the update.

These are all security issues fixed in the apache2-2.4.64-1.1 package on the GA media of openSUSE Tumbleweed.

This update for apache2 fixes the following issues:

Changes in apache2:

Version update to 2.4.66 (jsc#PED-16181)

*) SECURITY: CVE-2025-66200: Apache HTTP Server: mod_userdir+suexec bypass via AllowOverride FileInfo. mod_userdir+suexec bypass via AllowOverride FileInfo vulnerability in Apache HTTP Server. Users with access to use the RequestHeader directive in htaccess can cause some CGI scripts to run under an unexpected userid. This issue affects Apache HTTP Server: from 2.4.7 through 2.4.65. *) SECURITY: CVE-2025-65082: Apache HTTP Server: CGI environment variable override. Improper Neutralization of Escape, Meta, or Control Sequences vulnerability in Apache HTTP Server through environment variables set via the Apache configuration unexpectedly superseding variables calculated by the server for CGI programs. This issue affects Apache HTTP Server from 2.4.0 through 2.4.65. *) SECURITY: CVE-2025-59775: Apache HTTP Server: NTLM Leakage on Windows through UNC SSRF. Server-Side Request Forgery (SSRF) vulnerability in Apache HTTP Server on Windows with AllowEncodedSlashes On and MergeSlashes Off allows to potentially leak NTLM hashes to a malicious server via SSRF and malicious requests or content *) SECURITY: CVE-2025-58098: Apache HTTP Server: Server Side Includes adds query string to #exec cmd=... Apache HTTP Server 2.4.65 and earlier with Server Side Includes (SSI) enabled and mod_cgid (but not mod_cgi) passes the shell-escaped query string to #exec cmd="..." directives. This issue affects Apache HTTP Server before 2.4.66. *) SECURITY: CVE-2025-55753: Apache HTTP Server: mod_md (ACME), unintended retry intervals An integer overflow in the case of failed ACME certificate renewal leads, after a number of failures (~30 days in default configurations), to the backoff timer becoming 0. Attempts to renew the certificate then are repeated without delays until it succeeds. This issue affects Apache HTTP Server: from 2.4.30 before 2.4.66. *) mod_http2: Fix handling of 304 responses from mod_cache. *) mod_http2/mod_proxy_http2: fix a bug in calculating the log2 value of integers, used in push diaries and proxy window size calculations. *) mod_md: update to version 2.6.5 - New directive MDInitialDelay, controlling how longer to wait after a server restart before checking certificates for renewal. [Michael Kaufmann] - Hardening: when build with OpenSSL older than 1.0.2 or old libressl versions, the parsing of ASN.1 time strings did not do a length check. - Hardening: when reading back OCSP responses stored in the local JSON store, missing 'valid' key led to uninitialized values, resulting in wrong refresh behaviour. *) mod_md: update to version 2.6.6 - Fix a small memory leak when using OpenSSL's BIGNUMs. - Fix reuse of curl easy handles by resetting them. *) mod_http2: update to version 2.0.35 New directive H2MaxStreamErrors to control how much bad behaviour by clients is tolerated before the connection is closed. *) mod_proxy_http2: add support for ProxyErrorOverride directive. *) mpm_common: Add new ListenTCPDeferAccept directive that allows to specify the value set for the TCP_DEFER_ACCEPT socket option on listen sockets. *) mod_ssl: Add SSLVHostSNIPolicy directive to control the virtual host compatibility policy. *) mod_md: update to version 2.6.2 - Fix error retry delay calculation to not already doubling the wait on the first error. *) mod_md: update to version 2.6.1 - Increasing default MDRetryDelay to 30 seconds to generate less bursty traffic on errored renewals for the ACME CA. This leads to error retries of 30s, 1 minute, 2, 4, etc. up to daily attempts. - Checking that configuring MDRetryDelay will result in a…

Root has patched CVE-2025-49630 in the rootio-apache2 package for Root:Debian:12. Multiple fixed versions available.

This update for apache2 fixes the following issues:

• CVE-2024-42516: Fixed HTTP response splitting. (bsc#1246477)
• CVE-2024-43204: Fixed a SSRF when mod_proxy is loaded that allows an attacker to send outbound proxy requests to a URL controlled by them. (bsc#1246305)
• CVE-2024-47252: Fixed insufficient escaping of user-supplied data in mod_ssl allows an untrusted SSL/TLS client to insert escape characters into log file. (bsc#1246303)
• CVE-2025-23048: Fixed access control bypass by trusted clients through TLS 1.3 session resumption in some mod_ssl configurations. (bsc#1246302)
• CVE-2025-49630: Fixed denial of service can be triggered by untrusted clients causing an assertion in mod_proxy_http2. (bsc#1246307)
• CVE-2025-49812: Fixed Opossum Attack Application Layer Desynchronization using Opportunistic TLS. (bsc#1246169)
• CVE-2025-53020: Fixed HTTP/2 denial of service due to late release of memory after effective lifetime. (bsc#1246306)

This update for apache2 fixes the following issues:

• CVE-2024-42516: Fixed HTTP response splitting. (bsc#1246477)
• CVE-2024-43204: Fixed a SSRF when mod_proxy is loaded that allows an attacker to send outbound proxy requests to a URL controlled by them. (bsc#1246305)
• CVE-2024-47252: Fixed insufficient escaping of user-supplied data in mod_ssl allows an untrusted SSL/TLS client to insert escape characters into log file. (bsc#1246303)
• CVE-2025-23048: Fixed access control bypass by trusted clients through TLS 1.3 session resumption in some mod_ssl configurations. (bsc#1246302)
• CVE-2025-49630: Fixed denial of service can be triggered by untrusted clients causing an assertion in mod_proxy_http2. (bsc#1246307)
• CVE-2025-49812: Fixed Opossum Attack Application Layer Desynchronization using Opportunistic TLS. (bsc#1246169)
• CVE-2025-53020: Fixed HTTP/2 denial of service due to late release of memory after effective lifetime. (bsc#1246306)

This update for apache2 fixes the following issues:

• CVE-2024-42516: Fixed HTTP response splitting. (bsc#1246477)
• CVE-2024-43204: Fixed a SSRF when mod_proxy is loaded that allows an attacker to send outbound proxy requests to a URL controlled by them. (bsc#1246305)
• CVE-2024-47252: Fixed insufficient escaping of user-supplied data in mod_ssl allows an untrusted SSL/TLS client to insert escape characters into log file. (bsc#1246303)
• CVE-2025-23048: Fixed access control bypass by trusted clients through TLS 1.3 session resumption in some mod_ssl configurations. (bsc#1246302)
• CVE-2025-49630: Fixed denial of service can be triggered by untrusted clients causing an assertion in mod_proxy_http2. (bsc#1246307)
• CVE-2025-49812: Fixed Opossum Attack Application Layer Desynchronization using Opportunistic TLS. (bsc#1246169)
• CVE-2025-53020: Fixed HTTP/2 denial of service due to late release of memory after effective lifetime. (bsc#1246306)

This update for apache2 fixes the following issues:

• CVE-2024-42516: Fixed HTTP response splitting. (bsc#1246477)
• CVE-2024-43204: Fixed a SSRF when mod_proxy is loaded that allows an attacker to send outbound proxy requests to a URL controlled by them. (bsc#1246305)
• CVE-2024-47252: Fixed insufficient escaping of user-supplied data in mod_ssl allows an untrusted SSL/TLS client to insert escape characters into log file. (bsc#1246303)
• CVE-2025-23048: Fixed access control bypass by trusted clients through TLS 1.3 session resumption in some mod_ssl configurations. (bsc#1246302)
• CVE-2025-49630: Fixed denial of service can be triggered by untrusted clients causing an assertion in mod_proxy_http2. (bsc#1246307)
• CVE-2025-49812: Fixed Opossum Attack Application Layer Desynchronization using Opportunistic TLS. (bsc#1246169)
• CVE-2025-53020: Fixed HTTP/2 denial of service due to late release of memory after effective lifetime. (bsc#1246306)

This update for apache2 fixes the following issues:

• CVE-2024-42516: Fixed HTTP response splitting. (bsc#1246477)
• CVE-2024-43204: Fixed a SSRF when mod_proxy is loaded that allows an attacker to send outbound proxy requests to a URL controlled by them. (bsc#1246305)
• CVE-2024-47252: Fixed insufficient escaping of user-supplied data in mod_ssl allows an untrusted SSL/TLS client to insert escape characters into log file. (bsc#1246303)
• CVE-2025-23048: Fixed access control bypass by trusted clients through TLS 1.3 session resumption in some mod_ssl configurations. (bsc#1246302)
• CVE-2025-49630: Fixed denial of service can be triggered by untrusted clients causing an assertion in mod_proxy_http2. (bsc#1246307)
• CVE-2025-49812: Fixed Opossum Attack Application Layer Desynchronization using Opportunistic TLS. (bsc#1246169)
• CVE-2025-53020: Fixed HTTP/2 denial of service due to late release of memory after effective lifetime. (bsc#1246306)

This update for apache2 fixes the following issues:

Changes in apache2:

Version update to 2.4.66 (jsc#PED-16181)

*) SECURITY: CVE-2025-66200: Apache HTTP Server: mod_userdir+suexec bypass via AllowOverride FileInfo. mod_userdir+suexec bypass via AllowOverride FileInfo vulnerability in Apache HTTP Server. Users with access to use the RequestHeader directive in htaccess can cause some CGI scripts to run under an unexpected userid. This issue affects Apache HTTP Server: from 2.4.7 through 2.4.65. *) SECURITY: CVE-2025-65082: Apache HTTP Server: CGI environment variable override. Improper Neutralization of Escape, Meta, or Control Sequences vulnerability in Apache HTTP Server through environment variables set via the Apache configuration unexpectedly superseding variables calculated by the server for CGI programs. This issue affects Apache HTTP Server from 2.4.0 through 2.4.65. *) SECURITY: CVE-2025-59775: Apache HTTP Server: NTLM Leakage on Windows through UNC SSRF. Server-Side Request Forgery (SSRF) vulnerability in Apache HTTP Server on Windows with AllowEncodedSlashes On and MergeSlashes Off allows to potentially leak NTLM hashes to a malicious server via SSRF and malicious requests or content *) SECURITY: CVE-2025-58098: Apache HTTP Server: Server Side Includes adds query string to #exec cmd=... Apache HTTP Server 2.4.65 and earlier with Server Side Includes (SSI) enabled and mod_cgid (but not mod_cgi) passes the shell-escaped query string to #exec cmd="..." directives. This issue affects Apache HTTP Server before 2.4.66. *) SECURITY: CVE-2025-55753: Apache HTTP Server: mod_md (ACME), unintended retry intervals An integer overflow in the case of failed ACME certificate renewal leads, after a number of failures (~30 days in default configurations), to the backoff timer becoming 0. Attempts to renew the certificate then are repeated without delays until it succeeds. This issue affects Apache HTTP Server: from 2.4.30 before 2.4.66. *) mod_http2: Fix handling of 304 responses from mod_cache. *) mod_http2/mod_proxy_http2: fix a bug in calculating the log2 value of integers, used in push diaries and proxy window size calculations. *) mod_md: update to version 2.6.5 - New directive MDInitialDelay, controlling how longer to wait after a server restart before checking certificates for renewal. [Michael Kaufmann] - Hardening: when build with OpenSSL older than 1.0.2 or old libressl versions, the parsing of ASN.1 time strings did not do a length check. - Hardening: when reading back OCSP responses stored in the local JSON store, missing 'valid' key led to uninitialized values, resulting in wrong refresh behaviour. *) mod_md: update to version 2.6.6 - Fix a small memory leak when using OpenSSL's BIGNUMs. - Fix reuse of curl easy handles by resetting them. *) mod_http2: update to version 2.0.35 New directive H2MaxStreamErrors to control how much bad behaviour by clients is tolerated before the connection is closed. *) mod_proxy_http2: add support for ProxyErrorOverride directive. *) mpm_common: Add new ListenTCPDeferAccept directive that allows to specify the value set for the TCP_DEFER_ACCEPT socket option on listen sockets. *) mod_ssl: Add SSLVHostSNIPolicy directive to control the virtual host compatibility policy. *) mod_md: update to version 2.6.2 - Fix error retry delay calculation to not already doubling the wait on the first error. *) mod_md: update to version 2.6.1 - Increasing default MDRetryDelay to 30 seconds to generate less bursty traffic on errored renewals for the ACME CA. This leads to error retries of 30s, 1 minute, 2, 4, etc. up to daily attempts. - Checking that configuring MDRetryDelay will result in a…

This update for apache2 fixes the following issues

• CVE-2026-23918: http2: double free and possible RCE on early reset (bsc#1263957).
• CVE-2026-24072: mod_rewrite elevation of privileges via ap_expr (bsc#1263935).
• CVE-2026-28780: heap buffer overflow in mod_proxy_ajp via ajp_msg_check_header() (bsc#1264163).
• CVE-2026-29167: mod_ldap per-dir use-after-free (bsc#1267976).
• CVE-2026-29168: allocation of resources without limits in mod_md via OCSP response (bsc#1264150).
• CVE-2026-29169: NULL pointer dereference in mod_dav_lock allows server crash via malicious requests (bsc#1263956).
• CVE-2026-29170: mod_proxy_ftp XSS (bsc#1267977).
• CVE-2026-33006: mod_auth_digest timing attack allows bypass of Digest authentication (bsc#1263955).
• CVE-2026-33007: NULL pointer dereference in mod_authn_socache allows unauthenticated remote user to crash a child processes (bsc#1263954).
• CVE-2026-33523: HTTP response splitting forwarding malicious status line (bsc#1263953).
• CVE-2026-33857: off-by-one OOB reads in AJP getter functions (bsc#1263952).
• CVE-2026-34032: heap buffer overread in mod_proxy_ajp due to missing null-termination check (bsc#1263951).
• CVE-2026-34059: heap buffer overread and memory disclosure via ajp_parse_data() (bsc#1263950).
• CVE-2026-34355: mod_proxy_html buffer overflow (bsc#1267978).
• CVE-2026-34356: malicious backend servers can lead to a heap-based buffer overflow (bsc#1267955).
• CVE-2026-42535: malicious path manipulation can lead to child process crashes (bsc#1267956).
• CVE-2026-42536: processing untrusted content can lead to a heap-based buffer overflow (bsc#1267962).
• CVE-2026-43951: out-of-bound read in merge_response_headers can cause crash (bsc#1267963).
• CVE-2026-44119: improper privilege management can lead to an unauthorized read (bsc#1267965).
• CVE-2026-44185: Stack Buffer Over-Read in mod_ssl OCSP send_request (bsc#1267969).
• CVE-2026-44186: responses from an attacker-controlled FTP backend can lead to resource exhaustion and a denial of service (bsc#1267970).
• CVE-2026-44631: crafted regular expression can lead to a buffer underwrite (bsc#1267971).
• CVE-2026-48913: file handle exhaustion during request processing in mod_http2 can lead to a use-after-free (bsc#1267972).
• CVE-2026-49975: Fix cookie header accounting against LimitRequestFields (bsc#1267503).

Non security issue:

• Update to 2.4.66 (jsc#PED-16334).

It was discovered that the Apache HTTP Server incorrectly handled certain Content-Type response headers. A remote attacker could possibly use this issue to perform HTTP response splitting attacks. (CVE-2024-42516)

xiaojunjie discovered that the Apache HTTP Server mod_proxy module incorrectly handled certain requests. A remote attacker could possibly use this issue to send outbound proxy requests to an arbitrary URL. (CVE-2024-43204)

John Runyon discovered that the Apache HTTP Server mod_ssl module incorrectly escaped certain data. A remote attacker could possibly use this issue to insert escape characters into log files. (CVE-2024-47252)

Sven Hebrok, Felix Cramer, Tim Storm, Maximilian Radoy, and Juraj Somorovsky discovered that the Apache HTTP Server mod_ssl module incorrectly handled TLS 1.3 session resumption. A remote attacker could possibly use this issue to bypass access control. (CVE-2025-23048)

Anthony CORSIEZ discovered that the Apache HTTP Server mod_proxy_http2 module incorrectly handled missing host headers. A remote attacker could possibly use this issue to cause the server to crash, resulting in a denial of service. (CVE-2025-49630)

Robert Merget discovered that the Apache HTTP Server mod_ssl module incorrectly handled TLS upgrades. A remote attacker could possibly use this issue to hijack an HTTP session. This update removes the old "SSLEngine optional" configuration option, possibly requiring a configuration change in certain environments. (CVE-2025-49812)

Gal Bar Nahum discovered that the Apache HTTP Server incorrectly handled certain memory operations. A remote attacker could possibly use this issue to cause the server to consume resources, leading to a denial of service. (CVE-2025-53020)

USN-7639-1 fixed several vulnerabilities in Apache. This update provides the corresponding update for Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, and addressed a regression fix (LP: #2119395). CVE-2025-49630 and CVE-2025-53020 only affected Ubuntu 18.04 LTS and Ubuntu 20.04 LTS.

Original advisory details:

It was discovered that the Apache HTTP Server incorrectly handled certain Content-Type response headers. A remote attacker could possibly use this issue to perform HTTP response splitting attacks. (CVE-2024-42516)

xiaojunjie discovered that the Apache HTTP Server mod_proxy module incorrectly handled certain requests. A remote attacker could possibly use this issue to send outbound proxy requests to an arbitrary URL. (CVE-2024-43204)

John Runyon discovered that the Apache HTTP Server mod_ssl module incorrectly escaped certain data. A remote attacker could possibly use this issue to insert escape characters into log files. (CVE-2024-47252)

Sven Hebrok, Felix Cramer, Tim Storm, Maximilian Radoy, and Juraj Somorovsky discovered that the Apache HTTP Server mod_ssl module incorrectly handled TLS 1.3 session resumption. A remote attacker could possibly use this issue to bypass access control. (CVE-2025-23048)

Anthony CORSIEZ discovered that the Apache HTTP Server mod_proxy_http2 module incorrectly handled missing host headers. A remote attacker could possibly use this issue to cause the server to crash, resulting in a denial of service. (CVE-2025-49630)

Robert Merget discovered that the Apache HTTP Server mod_ssl module incorrectly handled TLS upgrades. A remote attacker could possibly use this issue to hijack an HTTP session. This update removes the old "SSLEngine optional" configuration option, possibly requiring a configuration change in certain environments. (CVE-2025-49812)

Gal Bar Nahum discovered that the Apache HTTP Server incorrectly handled certain memory operations. A remote attacker could possibly use this issue to cause the server to consume resources, leading to a denial of service. (CVE-2025-53020)