In some mod_ssl configurations on Apache HTTP Server versions through to 2.4.63, an HTTP desynchronisation attack allows a man-in-the-middle attacker to hijack an HTTP session via a TLS upgrade.
Only configurations using "SSLEngine optional" to enable TLS upgrades are affected. Users are recommended to upgrade to version 2.4.64, which removes support for TLS upgrade.
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alma_linux | — | Upgrade mod_ldapUpgrade mod_http2Upgrade httpd-coreUpgrade mod_sessionUpgrade httpd-manualUpgrade mod_sslUpgrade httpd-filesystemUpgrade mod_luaUpgrade httpd-develUpgrade httpd-toolsUpgrade mod_proxy_htmlUpgrade httpdUpgrade mod_md | Sep 5, 2025 | Sep 3, 2025 |
| Alpine Linux | — | Upgrade apache2 | Aug 8, 2025 | Jul 10, 2025 |
| Amazon Linux Ami 2 | — | Upgrade mod_ldapUpgrade mod_sessionUpgrade httpd-filesystemUpgrade httpdUpgrade mod_sslUpgrade httpd-toolsUpgrade httpd-debuginfoUpgrade httpd-manualUpgrade httpd-develUpgrade mod_proxy_htmlUpgrade mod_md | May 20, 2026 | May 20, 2026 |
| Amazon_linux_2023 | — | Upgrade mod_ldap-debuginfoUpgrade httpd-filesystemUpgrade mod_ssl-debuginfoUpgrade mod_sslUpgrade httpd-debuginfoUpgrade mod_proxy_htmlUpgrade mod_session-debuginfoUpgrade mod_ldapUpgrade mod_sessionUpgrade mod_proxy_html-debuginfoUpgrade mod_luaUpgrade httpd-tools-debuginfoUpgrade httpd-develUpgrade httpdUpgrade httpd-toolsUpgrade httpd-coreUpgrade httpd-core-debuginfoUpgrade httpd-manualUpgrade mod_lua-debuginfoUpgrade httpd-debugsource | Aug 5, 2025 | Jul 14, 2025 |
| Apache Httpd | — | Upgrade to the latest version of Apache HTTPD | Jul 18, 2025 | Jul 10, 2025 |
| Debian | — | Upgrade apache2 | Jul 14, 2025 | Jul 10, 2025 |
| Freebsd | — | Upgrade apache24 | Jul 13, 2025 | Jul 11, 2025 |
| Gentoo Linux | — | Upgrade www-servers/apache. | Aug 16, 2026 | Aug 13, 2026 |
| Huawei Euleros 2_0_sp10 | — | Upgrade httpdUpgrade httpd-toolsUpgrade mod_sslUpgrade httpd-filesystem | Nov 12, 2025 | Sep 9, 2025 |
| Huawei Euleros 2_0_sp11 | — | Upgrade httpd-toolsUpgrade mod_sslUpgrade httpdUpgrade httpd-filesystem | Oct 14, 2025 | Sep 9, 2025 |
| Huawei Euleros 2_0_sp12 | — | Upgrade httpdUpgrade mod_sslUpgrade httpd-toolsUpgrade httpd-filesystem | Sep 15, 2025 | Sep 9, 2025 |
| Huawei Euleros 2_0_sp13 | — | Upgrade httpdUpgrade httpd-filesystemUpgrade mod_sslUpgrade httpd-tools | Oct 24, 2025 | Sep 9, 2025 |
| Oracle_linux | — | Upgrade mod_http2Upgrade mod_ldapUpgrade mod_proxy_htmlUpgrade mod_luaUpgrade httpd-filesystemUpgrade httpd-toolsUpgrade httpd-coreUpgrade mod_mdUpgrade httpd-manualUpgrade httpdUpgrade httpd-develUpgrade mod_sslUpgrade mod_session | Sep 3, 2025 | Jul 14, 2025 |
| Redhat_linux | — | Upgrade httpd-manualUpgrade mod_http2-debugsourceUpgrade httpd-debuginfoUpgrade mod_http2Upgrade httpd-debugsourceUpgrade httpd-coreUpgrade mod_lua-debuginfoUpgrade mod_proxy_html-debuginfoUpgrade mod_session-debuginfoUpgrade httpd-filesystemUpgrade mod_sslUpgrade mod_sessionUpgrade mod_md-debuginfoUpgrade mod_ldapUpgrade httpd-tools-debuginfoUpgrade mod_http2-debuginfoUpgrade httpd-core-debuginfoUpgrade mod_md-debugsourceUpgrade mod_luaUpgrade mod_ssl-debuginfoUpgrade httpd-toolsUpgrade httpd-develUpgrade httpdUpgrade mod_ldap-debuginfoUpgrade mod_mdUpgrade mod_proxy_html | Jul 15, 2025 | Jul 10, 2025 |
| Rocky_linux | — | Upgrade mod_http2-debuginfoUpgrade mod_proxy_htmlUpgrade httpd-toolsUpgrade httpdUpgrade mod_ssl-debuginfoUpgrade mod_ldap-debuginfoUpgrade httpd-debuginfoUpgrade mod_mdUpgrade mod_md-debugsourceUpgrade httpd-develUpgrade mod_sslUpgrade mod_md-debuginfoUpgrade httpd-core-debuginfoUpgrade mod_sessionUpgrade httpd-tools-debuginfoUpgrade httpd-debugsourceUpgrade mod_http2-debugsourceUpgrade mod_http2Upgrade mod_session-debuginfoUpgrade mod_proxy_html-debuginfoUpgrade mod_ldapUpgrade mod_lua-debuginfoUpgrade httpd-coreUpgrade mod_lua | Feb 5, 2026 | Sep 8, 2025 |
| Suse | — | Upgrade apache2-tls13-preforkUpgrade apache2-tls13Upgrade apache2-develUpgrade apache2Upgrade apache2-preforkUpgrade apache2-workerUpgrade apache2-tls13-example-pagesUpgrade apache2-example-pagesUpgrade apache2-tls13-workerUpgrade apache2-tls13-develUpgrade apache2-tls13-docUpgrade apache2-tls13-utilsUpgrade apache2-utilsUpgrade apache2-docUpgrade apache2-manualUpgrade apache2-event | Dec 5, 2025 | Sep 9, 2025 |
| Ubuntu | — | Upgrade apache2Upgrade apache2 (Ubuntu Pro) | Jul 17, 2025 | Jul 10, 2025 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | Aug 11, 2025 | Jul 10, 2025 |
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