CVE-2023-45802

When a HTTP/2 stream was reset (RST frame) by a client, there was a time window were the request's memory resources were not reclaimed immediately. Instead, de-allocation was deferred to connection close. A client could send new requests and resets, keeping the connection busy and open and causing the memory footprint to keep on growing. On connection close, all resources were reclaimed, but the process might run out of memory before that.

This was found by the reporter during testing of CVE-2023-44487 (HTTP/2 Rapid Reset Exploit) with their own test client. During "normal" HTTP/2 use, the probability to hit this bug is very low. The kept memory would not become noticeable before the connection closes or times out.

Users are recommended to upgrade to version 2.4.58, which fixes the issue.

When a HTTP/2 stream was reset (RST frame) by a client, there was a time window were the request's memory resources were not reclaimed immediately. Instead, de-allocation was deferred to connection close. A client could send new requests and resets, keeping the connection busy and open and causing the memory footprint to keep on growing. On connection close, all resources were reclaimed, but the process might run out of memory before that.

This was found by the reporter during testing of CVE-2023-44487 (HTTP/2 Rapid Reset Exploit) with their own test client. During "normal" HTTP/2 use, the probability to hit this bug is very low. The kept memory would not become noticeable before the connection closes or times out.

Users are recommended to upgrade to version 2.4.58, which fixes the issue.

When a HTTP/2 stream was reset (RST frame) by a client, there was a time window were the request's memory resources were not reclaimed immediately. Instead, de-allocation was deferred to connection close. A client could send new requests and resets, keeping the connection busy and open and causing the memory footprint to keep on growing. On connection close, all resources were reclaimed, but the process might run out of memory before that. This was found by the reporter during testing of CVE-2023-44487 (HTTP/2 Rapid Reset Exploit) with their own test client. During "normal" HTTP/2 use, the probability to hit this bug is very low. The kept memory would not become noticeable before the connection closes or times out. Users are recommended to upgrade to version 2.4.58, which fixes the issue.

Apache HTTP Server is a powerful and flexible HTTP/1.1 compliant web server.

Security Fix(es):

Out-of-bounds Read vulnerability in mod_macro of Apache HTTP Server.This issue affects Apache HTTP Server: through 2.4.57.

(CVE-2023-31122)

When a HTTP/2 stream was reset (RST frame) by a client, there was a time window were the request's memory resources were not reclaimed immediately. Instead, de-allocation was deferred to connection close. A client could send new requests and resets, keeping the connection busy and open and causing the memory footprint to keep on growing. On connection close, all resources were reclaimed, but the process might run out of memory before that.

This was found by the reporter during testing of CVE-2023-44487 (HTTP/2 Rapid Reset Exploit) with their own test client. During "normal" HTTP/2 use, the probability to hit this bug is very low. The kept memory would not become noticeable before the connection closes or times out.

Users are recommended to upgrade to version 2.4.58, which fixes the issue. (CVE-2023-45802)

Apache HTTP Server is a powerful and flexible HTTP/1.1 compliant web server.

Security Fix(es):

When a HTTP/2 stream was reset (RST frame) by a client, there was a time window were the request's memory resources were not reclaimed immediately. Instead, de-allocation was deferred to connection close. A client could send new requests and resets, keeping the connection busy and open and causing the memory footprint to keep on growing. On connection close, all resources were reclaimed, but the process might run out of memory before that.

This was found by the reporter during testing of CVE-2023-44487 (HTTP/2 Rapid Reset Exploit) with their own test client. During "normal" HTTP/2 use, the probability to hit this bug is very low. The kept memory would not become noticeable before the connection closes or times out.

Users are recommended to upgrade to version 2.4.58, which fixes the issue. (CVE-2023-45802)

Apache HTTP Server is a powerful and flexible HTTP/1.1 compliant web server.

Security Fix(es):

Out-of-bounds Read vulnerability in mod_macro of Apache HTTP Server.This issue affects Apache HTTP Server: through 2.4.57.

(CVE-2023-31122)

When a HTTP/2 stream was reset (RST frame) by a client, there was a time window were the request's memory resources were not reclaimed immediately. Instead, de-allocation was deferred to connection close. A client could send new requests and resets, keeping the connection busy and open and causing the memory footprint to keep on growing. On connection close, all resources were reclaimed, but the process might run out of memory before that.

This was found by the reporter during testing of CVE-2023-44487 (HTTP/2 Rapid Reset Exploit) with their own test client. During "normal" HTTP/2 use, the probability to hit this bug is very low. The kept memory would not become noticeable before the connection closes or times out.

Users are recommended to upgrade to version 2.4.58, which fixes the issue. (CVE-2023-45802)

Apache HTTP Server is a powerful and flexible HTTP/1.1 compliant web server.

Security Fix(es):

Out-of-bounds Read vulnerability in mod_macro of Apache HTTP Server.This issue affects Apache HTTP Server: through 2.4.57.

(CVE-2023-31122)

When a HTTP/2 stream was reset (RST frame) by a client, there was a time window were the request's memory resources were not reclaimed immediately. Instead, de-allocation was deferred to connection close. A client could send new requests and resets, keeping the connection busy and open and causing the memory footprint to keep on growing. On connection close, all resources were reclaimed, but the process might run out of memory before that.

This was found by the reporter during testing of CVE-2023-44487 (HTTP/2 Rapid Reset Exploit) with their own test client. During "normal" HTTP/2 use, the probability to hit this bug is very low. The kept memory would not become noticeable before the connection closes or times out.

Users are recommended to upgrade to version 2.4.58, which fixes the issue. (CVE-2023-45802)

Apache HTTP Server is a powerful and flexible HTTP/1.1 compliant web server.

Security Fix(es):

Out-of-bounds Read vulnerability in mod_macro of Apache HTTP Server.This issue affects Apache HTTP Server: through 2.4.57.

(CVE-2023-31122)

When a HTTP/2 stream was reset (RST frame) by a client, there was a time window were the request's memory resources were not reclaimed immediately. Instead, de-allocation was deferred to connection close. A client could send new requests and resets, keeping the connection busy and open and causing the memory footprint to keep on growing. On connection close, all resources were reclaimed, but the process might run out of memory before that.

This was found by the reporter during testing of CVE-2023-44487 (HTTP/2 Rapid Reset Exploit) with their own test client. During "normal" HTTP/2 use, the probability to hit this bug is very low. The kept memory would not become noticeable before the connection closes or times out.

Users are recommended to upgrade to version 2.4.58, which fixes the issue. (CVE-2023-45802)

When a HTTP/2 stream was reset (RST frame) by a client, there was a time window were the request's memory resources were not reclaimed immediately. Instead, de-allocation was deferred to connection close. A client could send new requests and resets, keeping the connection busy and open and causing the memory footprint to keep on growing. On connection close, all resources were reclaimed, but the process might run out of memory before that. This was found by the reporter during testing of CVE-2023-44487 (HTTP/2 Rapid Reset Exploit) with their own test client. During "normal" HTTP/2 use, the probability to hit this bug is very low. The kept memory would not become noticeable before the connection closes or times out. Users are recommended to upgrade to version 2.4.58, which fixes the issue.

The mod_http2 Apache httpd module implements the HTTP2 protocol (h2+h2c) on top of libnghttp2 for httpd 2.4 servers.

Security Fix(es):

• httpd: mod_http2: DoS in HTTP/2 with initial window size 0 (CVE-2023-43622)
• mod_http2: reset requests exhaust memory (incomplete fix of CVE-2023-44487) (CVE-2023-45802)

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.

Additional Changes:

For detailed information on changes in this release, see the AlmaLinux Release Notes linked from the References section.

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

Security Fix(es):

• httpd: mod_macro: out-of-bounds read vulnerability (CVE-2023-31122)
• mod_http2: reset requests exhaust memory (incomplete fix of CVE-2023-44487) (CVE-2023-45802)

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.

Additional Changes:

For detailed information on changes in this release, see the AlmaLinux Release Notes linked from the References section.

When a HTTP/2 stream was reset (RST frame) by a client, there was a time window were the request's memory resources were not reclaimed immediately. Instead, de-allocation was deferred to connection close. A client could send new requests and resets, keeping the connection busy and open and causing the memory footprint to keep on growing. On connection close, all resources were reclaimed, but the process might run out of memory before that.

This was found by the reporter during testing of CVE-2023-44487 (HTTP/2 Rapid Reset Exploit) with their own test client. During "normal" HTTP/2 use, the probability to hit this bug is very low. The kept memory would not become noticeable before the connection closes or times out.

Users are recommended to upgrade to version 2.4.58, which fixes the issue.

• CVE-2023-45802: fix deferred memory reclaim of reset HTTP/2 streams

When a HTTP/2 stream was reset (RST frame) by a client, there was a time window were the request's memory resources were not reclaimed immediately. Instead, de-allocation was deferred to connection close. A client could send new requests and resets, keeping the connection busy and open and causing the memory footprint to keep on growing. On connection close, all resources were reclaimed, but the process might run out of memory before that.

This was found by the reporter during testing of CVE-2023-44487 (HTTP/2 Rapid Reset Exploit) with their own test client. During "normal" HTTP/2 use, the probability to hit this bug is very low. The kept memory would not become noticeable before the connection closes or times out.

Users are recommended to upgrade to version 2.4.58, which fixes the issue.

Apache has been updated to version 2.4.58 to fix several security issues.

CVE-2023-45802: Apache HTTP Server: HTTP/2 stream memory not reclaimed right away on RST (cve.mitre.org) When a HTTP/2 stream was reset (RST frame) by a client, there was a time window were the request's memory resources were not reclaimed immediately. Instead, de-allocation was deferred to connection close. A client could send new requests and resets, keeping the connection busy and open and causing the memory footprint to keep on growing. On connection close, all resources were reclaimed, but the process might run out of memory before that. This was found by the reporter during testing of CVE-2023-44487 (HTTP/2 Rapid Reset Exploit) with their own test client. During "normal" HTTP/2 use, the probability to hit this bug is very low. The kept memory would not become noticeable before the connection closes or times out. Users are recommended to upgrade to version 2.4.58, which fixes the issue. Credits: Will Dormann of Vul Labs

CVE-2023-43622: Apache HTTP Server: DoS in HTTP/2 with initial windows size 0 (cve.mitre.org) An attacker, opening a HTTP/2 connection with an initial window size of 0, was able to block handling of that connection indefinitely in Apache HTTP Server. This could be used to exhaust worker resources in the server, similar to the well known "slow loris" attack pattern. This has been fixed in version 2.4.58, so that such connection are terminated properly after the configured connection timeout. This issue affects Apache HTTP Server: from 2.4.55 through 2.4.57. Users are recommended to upgrade to version 2.4.58, which fixes the issue. Credits: Prof. Sven Dietrich (City University of New York)

CVE-2023-31122: mod_macro buffer over-read (cve.mitre.org) Out-of-bounds Read vulnerability in mod_macro of Apache HTTP Server. This issue affects Apache HTTP Server: through 2.4.57. Credits: David Shoon (github/davidshoon)

These are all security issues fixed in the apache2-2.4.58-1.1 package on the GA media of openSUSE Tumbleweed.

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

Security Fix(es):

• httpd: mod_macro: out-of-bounds read vulnerability (CVE-2023-31122)

• mod_http2: reset requests exhaust memory (incomplete fix of CVE-2023-44487) (CVE-2023-45802)

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.

Additional Changes:

For detailed information on changes in this release, see the Rocky Linux 8.10 Release Notes linked from the References section.

This update for apache2 fixes the following issues:

• CVE-2023-45802: HTTP/2 stream memory not reclaimed right away on RST (bsc#1216423).

This update for apache2 fixes the following issues:

• CVE-2023-45802: HTTP/2 stream memory not reclaimed right away on RST (bsc#1216423).

This update for apache2 fixes the following issues:

• CVE-2023-45802: HTTP/2 stream memory not reclaimed right away on RST (bsc#1216423).

This update for apache2 fixes the following issues:

• CVE-2023-45802: Fixed regression with previous fix (bsc#1233165).

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).

David Shoon discovered that the Apache HTTP Server mod_macro module incorrectly handled certain memory operations. A remote attacker could possibly use this issue to cause the server to crash, resulting in a denial of service. (CVE-2023-31122)

Prof. Sven Dietrich, Isa Jafarov, Prof. Heejo Lee, and Choongin Lee discovered that the Apache HTTP Server incorrectly handled certain HTTP/2 connections. A remote attacker could possibly use this issue to cause the server to consume resources, leading to a denial of service. This issue only affected Ubuntu 23.04, and Ubuntu 23.10. (CVE-2023-43622)

Will Dormann and David Warren discovered that the Apache HTTP Server incorrectly handled memory when handling HTTP/2 connections. A remote attacker could possibly use this issue to cause the server to consume resources, leading to a denial of service. (CVE-2023-45802)

It was discovered that Apache HTTP Server incorrectly handled certain response headers. An attacker could possibly use this issue to perform HTTP response splitting attacks. This issue only affected Ubuntu 14.04 LTS. (CVE-2023-38709)

Will Dormann and David Warren discovered that Apache HTTP Server's HTTP/2 implementation did not properly reclaim memory when streams were reset by clients. A remote attacker could possibly use this issue to cause Apache HTTP Server to consume resources, leading to a denial of service. This issue only affected Ubuntu 18.04 LTS. (CVE-2023-45802)

Keran Mu and Jianjun Chen discovered that Apache HTTP Server incorrectly handled certain response headers. An attacker could possibly use this issue to perform HTTP response splitting attacks. This issue only affected Ubuntu 14.04 LTS. (CVE-2024-24795)

Orange Tsai discovered that Apache HTTP Server mod_proxy incorrectly handled URL encoding. A remote attacker could possibly use this issue to bypass authentication via crafted requests. This issue only affected Ubuntu 16.04 LTS and Ubuntu 18.04 LTS. (CVE-2024-38473)

Orange Tsai discovered that Apache HTTP Server could be caused to perform server-side request forgery (SSRF) via malicious backend response headers. A remote attacker could possibly use this issue to conduct SSRF attacks or disclose sensitive information. This issue only affected Ubuntu 14.04 LTS. (CVE-2024-38476)

Orange Tsai discovered that Apache HTTP Server mod_proxy did not properly handle certain null pointer conditions. A remote attacker could possibly use this issue to cause Apache HTTP Server to crash, resulting in a denial of service. This issue only affected Ubuntu 14.04 LTS. (CVE-2024-38477)

Orange Tsai discovered that Apache HTTP Server mod_rewrite could be made to perform server-side request forgery (SSRF) via unsafe RewriteRules. A remote attacker could possibly use this issue to conduct SSRF attacks. This issue only affected Ubuntu 16.04 LTS and Ubuntu 18.04 LTS. (CVE-2024-39573)

It was discovered that Apache HTTP Server incorrectly handled certain response headers. An attacker could possibly use this issue to perform HTTP response splitting attacks. This issue only affected Ubuntu 14.04 LTS. (CVE-2024-42516)

It was discovered that Apache HTTP Server could be caused to perform server-side request forgery (SSRF) via mod_headers modifying Content-Type headers. A remote attacker could possibly use this issue to conduct SSRF attacks. This issue only affected Ubuntu 14.04 LTS. (CVE-2024-43204)

John Runyon discovered that Apache HTTP Server mod_ssl did not properly escape user-supplied data before writing log entries. A remote attacker could possibly use this issue to insert escape sequences into log files. This issue only affected Ubuntu 14.04 LTS. (CVE-2024-47252)

Robert Merget discovered that Apache HTTP Server with SSLEngine optional was vulnerable to HTTP desynchronisation attacks. An attacker in a privileged network position could possibly use this issue to hijack HTTP sessions. This issue only affected Ubuntu 14.04 LTS. (CVE-2025-49812)

It was discovered that Apache HTTP Server mod_md had an integer overflow in the ACME certificate renewal backoff timer. An attacker could possibly use this issue to cause excessive certificate renewal requests. This issue only affected Ubuntu 20.04 LTS. (CVE-2025-55753)

Anthony Parfenov discovered that Apache HTTP Server with SSI enabled and mod_cgid passed shell-escaped query strings to #exec cmd directives. A remote attacker could possibly use this issue to perform command injection. (CVE-2025-58098)

Mattias Åsander discovered that Apache HTTP Server incorrectly gave precedence to environment variables from HTTP headers over server-calculated CGI variables. A remote attacker could possibly use this issue to influence the environment of CGI programs. (CVE-2025-65082)

Mattias Åsander discovered that Apache HTTP Server mod_userdir with suexec could be caused to run CGI scripts under…