CVE-2026-87865

When libcurl uses libssh2 with a hashed known_hosts file, an unrelated initial entry can cause host key validation to report a key mismatch as a missing key to the CURLOPT_SSH_KEYFUNCTION callback.

When libcurl uses libssh2 with a hashed known_hosts file, an unrelated initial entry can cause host key validation to report a key mismatch as a missing key to the CURLOPT_SSH_KEYFUNCTION callback.

When libcurl uses libssh2 with a hashed known_hosts file, an unrelated initial entry can cause host key validation to report a key mismatch as a missing key to the CURLOPT_SSH_KEYFUNCTION callback.

When libcurl uses libssh2 with a hashed known_hosts file, an unrelated initial entry can cause host key validation to report a key mismatch as a missing key to the CURLOPT_SSH_KEYFUNCTION callback.

When libcurl uses libssh2 with a hashed known_hosts file, an unrelated initial entry can cause host key validation to report a key mismatch as a missing key to the CURLOPT_SSH_KEYFUNCTION callback.

When libcurl uses libssh2 with a hashed known_hosts file, an unrelated initial entry can cause host key validation to report a key mismatch as a missing key to the CURLOPT_SSH_KEYFUNCTION callback.

When libcurl uses libssh2 with a hashed known_hosts file, an unrelated initial entry can cause host key validation to report a key mismatch as a missing key to the CURLOPT_SSH_KEYFUNCTION callback.

When libcurl uses libssh2 with a hashed known_hosts file, an unrelated initial entry can cause host key validation to report a key mismatch as a missing key to the CURLOPT_SSH_KEYFUNCTION callback.

When libcurl uses libssh2 with a hashed known_hosts file, an unrelated initial entry can cause host key validation to report a key mismatch as a missing key to the CURLOPT_SSH_KEYFUNCTION callback.

These are all security issues fixed in the curl-8.23.0-1.1 package on the GA media of openSUSE Tumbleweed.

Root has patched CVE-2026-87865 in the curl package for Root:Alpine:3.15. Multiple fixed versions available.

Root has patched CVE-2026-87865 in the curl package for Root:Alpine:3.21. Multiple fixed versions available.

Root has patched CVE-2026-87865 in the curl package for Root:Debian:12. Multiple fixed versions available.

Root has patched CVE-2026-87865 in the curl package for Root:Debian:13. Multiple fixed versions available.

It was discovered that curl, when built with GnuTLS support, had an out-of-bounds read in the WebSocket send path. An attacker could possibly use this issue to obtain sensitive information. (CVE-2026-107928)

Maksim discovered that curl did not correctly include the interface binding in connection reuse decisions when CURLOPT_INTERFACE was used. An attacker could possibly use this issue to cause connections to go out from an unintended source address. (CVE-2026-107929)

Stanislav Fort discovered that curl did not properly clear AWS SigV4 authentication state when CURLOPT_AWS_SIGV4 was set to NULL. An attacker could possibly use this issue to obtain sensitive information. (CVE-2026-86409)

Stanislav Fort discovered that the curl command line tool did not set SSH host verification options when following redirects to SFTP or SCP URLs. An attacker could possibly use this issue to perform machine-in-the-middle attacks. (CVE-2026-86410)

Stanislav Fort discovered that curl did not properly handle cookie jar entries that could not be reloaded. An attacker could possibly use this issue to cause a denial of service. (CVE-2026-86412)

Stanislav Fort discovered that an HTTP proxy could trick libcurl into sending credentials to the proxy itself by responding to a CONNECT request with an unexpected authentication challenge. An attacker could possibly use this issue to obtain sensitive information. (CVE-2026-86414)

Stanislav Fort discovered that curl did not correctly handle HSTS entries when an includeSubDomains parent entry was imported before a longer-lived child entry. An attacker could possibly use this issue to cause curl to use unencrypted HTTP connections. (CVE-2026-87862)

Stanislav Fort discovered that curl did not properly handle HSTS max-age values that exceeded calendar time structure bounds. An attacker could possibly use this issue to cause a denial of service or data loss. (CVE-2026-87863)

Stanislav Fort discovered that curl did not properly handle IMAP APPEND commands when CURLOPT_CRLF was enabled, allowing overflow bytes to be interpreted as pipelined commands. An authenticated attacker could possibly use this issue to inject arbitrary IMAP commands. (CVE-2026-87864)

Bobbeh Rhino discovered that libcurl, when used with libssh2 and a hashed known_hosts file, could misreport a host key mismatch as a missing key. An attacker could possibly use this issue to perform machine-in-the-middle attacks. (CVE-2026-87865)

Joshua Rogers discovered that curl did not properly handle long cookie entries written to a Netscape cookie jar. An attacker could possibly use this issue to cause a denial of service. (CVE-2026-92386)

Joshua Rogers discovered that a malicious FTP, IMAP, POP3, or SMTP server could cause libcurl to block indefinitely by omitting the final control-response line. An attacker could possibly use this issue to cause a denial of service. (CVE-2026-92387)

Joshua Rogers discovered that libcurl had a use-after-free vulnerability in the FTP wildcard matching code. An attacker could possibly use this issue to cause curl to crash, resulting in a denial of service, or execute arbitrary code. (CVE-2026-92388)

Joshua Rogers discovered that libcurl's TFTP state machine did not properly validate transfer directions, allowing a malicious server to force the client into transmit mode. An attacker could possibly use this issue to obtain sensitive information. (CVE-2026-92389)

Joshua Rogers discovered that curl did not properly enforce its file overwrite protection when using --remote-header-name in certain circumstances. An attacker could possibly use this issue to overwrite local files. (CVE-2026-92390)

Joshua Rogers discovered that curl had a stack overflow vulnerability when processing deeply nested MIME structures. An attacker could possibly use this issue to cause curl to crash, resulting in a denial of service. (CVE-2026-92391)

Joshua Rogers discovered that libcurl could expose credentials in the URL returned by…

USN-8927-1 fixed vulnerabilities in curl. This update provides the corresponding fixes for Ubuntu 26.10.

Original advisory details:

It was discovered that curl, when built with GnuTLS support, had an out-of-bounds read in the WebSocket send path. An attacker could possibly use this issue to obtain sensitive information. (CVE-2026-107928)

Maksim discovered that curl did not correctly include the interface binding in connection reuse decisions when CURLOPT_INTERFACE was used. An attacker could possibly use this issue to cause connections to go out from an unintended source address. (CVE-2026-107929)

Stanislav Fort discovered that curl did not properly clear AWS SigV4 authentication state when CURLOPT_AWS_SIGV4 was set to NULL. An attacker could possibly use this issue to obtain sensitive information. (CVE-2026-86409)

Stanislav Fort discovered that the curl command line tool did not set SSH host verification options when following redirects to SFTP or SCP URLs. An attacker could possibly use this issue to perform machine-in-the-middle attacks. (CVE-2026-86410)

Stanislav Fort discovered that curl did not properly handle cookie jar entries that could not be reloaded. An attacker could possibly use this issue to cause a denial of service. (CVE-2026-86412)

Stanislav Fort discovered that an HTTP proxy could trick libcurl into sending credentials to the proxy itself by responding to a CONNECT request with an unexpected authentication challenge. An attacker could possibly use this issue to obtain sensitive information. (CVE-2026-86414)

Stanislav Fort discovered that curl did not correctly handle HSTS entries when an includeSubDomains parent entry was imported before a longer-lived child entry. An attacker could possibly use this issue to cause curl to use unencrypted HTTP connections. (CVE-2026-87862)

Stanislav Fort discovered that curl did not properly handle HSTS max-age values that exceeded calendar time structure bounds. An attacker could possibly use this issue to cause a denial of service or data loss. (CVE-2026-87863)

Stanislav Fort discovered that curl did not properly handle IMAP APPEND commands when CURLOPT_CRLF was enabled, allowing overflow bytes to be interpreted as pipelined commands. An authenticated attacker could possibly use this issue to inject arbitrary IMAP commands. (CVE-2026-87864)

Bobbeh Rhino discovered that libcurl, when used with libssh2 and a hashed known_hosts file, could misreport a host key mismatch as a missing key. An attacker could possibly use this issue to perform machine-in-the-middle attacks. (CVE-2026-87865)

Joshua Rogers discovered that curl did not properly handle long cookie entries written to a Netscape cookie jar. An attacker could possibly use this issue to cause a denial of service. (CVE-2026-92386)

Joshua Rogers discovered that a malicious FTP, IMAP, POP3, or SMTP server could cause libcurl to block indefinitely by omitting the final control-response line. An attacker could possibly use this issue to cause a denial of service. (CVE-2026-92387)

Joshua Rogers discovered that libcurl had a use-after-free vulnerability in the FTP wildcard matching code. An attacker could possibly use this issue to cause curl to crash, resulting in a denial of service, or execute arbitrary code. (CVE-2026-92388)

Joshua Rogers discovered that libcurl's TFTP state machine did not properly validate transfer directions, allowing a malicious server to force the client into transmit mode. An attacker could possibly use this issue to obtain sensitive information. (CVE-2026-92389)

Joshua Rogers discovered that curl did not properly enforce its file overwrite protection when using --remote-header-name in certain circumstances. An attacker could possibly use this issue to overwrite local files. (CVE-2026-92390)

Joshua Rogers discovered that curl had a stack overflow vulnerability when processing deeply nested MIME structures. An attacker could…