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.
CVSS Details
- CVSS 3.1 Base Score: 7.5
- CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alma_linux | — | Upgrade mod_http2 | May 8, 2024 | Oct 23, 2023 |
| Alpine Linux | — | Upgrade apache2 | Mar 26, 2024 | Oct 23, 2023 |
| Amazon Linux Ami 2 | — | Upgrade httpd-debuginfoUpgrade httpd-develUpgrade httpd-filesystemUpgrade mod_proxy_htmlUpgrade mod_ldapUpgrade mod_sessionUpgrade mod_mdUpgrade httpd-manualUpgrade httpdUpgrade httpd-toolsUpgrade mod_ssl | Nov 3, 2023 | Oct 23, 2023 |
| Amazon_linux | — | Upgrade httpd24 | Nov 4, 2023 | Oct 23, 2023 |
| Amazon_linux_2023 | — | Upgrade httpd-coreUpgrade mod_lua-debuginfoUpgrade httpd-core-debuginfoUpgrade httpd-manualUpgrade mod_ldap-debuginfoUpgrade httpd-toolsUpgrade mod_ssl-debuginfoUpgrade httpdUpgrade httpd-debugsourceUpgrade httpd-develUpgrade httpd-debuginfoUpgrade mod_ldapUpgrade mod_sslUpgrade mod_luaUpgrade mod_proxy_html-debuginfoUpgrade httpd-tools-debuginfoUpgrade mod_sessionUpgrade mod_session-debuginfoUpgrade httpd-filesystemUpgrade mod_proxy_html | Feb 17, 2025 | Oct 10, 2023 |
| Apache Httpd | — | Upgrade to the latest version of Apache HTTPD | Nov 29, 2023 | Oct 23, 2023 |
| Debian | — | Upgrade apache2 | Apr 18, 2024 | Oct 23, 2023 |
| Freebsd | — | Upgrade apache24Upgrade varnish7 | Dec 10, 2025 | Oct 19, 2023 |
| Oracle_linux | — | Upgrade mod_http2 | May 8, 2024 | Oct 10, 2023 |
| Redhat_linux | — | Upgrade mod_http2-debuginfoUpgrade mod_http2-debugsourceUpgrade mod_http2 | May 1, 2024 | Oct 23, 2023 |
| Ubuntu | — | Upgrade apache2 | Nov 23, 2023 | Oct 23, 2023 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | Jan 20, 2025 | Oct 23, 2023 |
Prioritise with Active Threat Intelligence
With curated Threat Intelligence, you can see which vulnerabilities truly put you at risk, prioritize what matters most, and act before attackers do.
Explore Intelligence Hub