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 mod_proxy_htmlUpgrade httpd-filesystemUpgrade mod_mdUpgrade mod_sessionUpgrade httpdUpgrade httpd-manualUpgrade mod_ldapUpgrade mod_sslUpgrade httpd-tools | Nov 3, 2023 | Oct 23, 2023 |
| Amazon_linux | — | amazon-linux-upgrade-httpd24 | Nov 4, 2023 | Oct 23, 2023 |
| Amazon_linux_2023 | amazon-linux-2023-upgrade-httpdamazon-linux-2023-upgrade-httpd-coreamazon-linux-2023-upgrade-httpd-core-debuginfoamazon-linux-2023-upgrade-httpd-debuginfoamazon-linux-2023-upgrade-httpd-debugsourceamazon-linux-2023-upgrade-httpd-develamazon-linux-2023-upgrade-httpd-filesystemamazon-linux-2023-upgrade-httpd-manualamazon-linux-2023-upgrade-httpd-toolsamazon-linux-2023-upgrade-httpd-tools-debuginfoamazon-linux-2023-upgrade-mod-ldapamazon-linux-2023-upgrade-mod-ldap-debuginfoamazon-linux-2023-upgrade-mod-luaamazon-linux-2023-upgrade-mod-lua-debuginfoamazon-linux-2023-upgrade-mod-proxy-htmlamazon-linux-2023-upgrade-mod-proxy-html-debuginfoamazon-linux-2023-upgrade-mod-sessionamazon-linux-2023-upgrade-mod-session-debuginfoamazon-linux-2023-upgrade-mod-sslamazon-linux-2023-upgrade-mod-ssl-debuginfo | Feb 17, 2025 | Oct 10, 2023 | |
| Apache Httpd | apache-httpd-upgrade-latest | Nov 29, 2023 | Oct 23, 2023 | |
| Debian | — | Upgrade apache2 | Apr 18, 2024 | Oct 23, 2023 |
| Freebsd | — | Upgrade varnish7Upgrade apache24 | Dec 10, 2025 | Oct 19, 2023 |
| Oracle_linux | — | oracle-linux-upgrade-mod-http2 | May 8, 2024 | Oct 10, 2023 |
| Redhat_linux | — | Upgrade mod_http2-debuginfoUpgrade mod_http2Upgrade mod_http2-debugsource | May 1, 2024 | Oct 23, 2023 |
| Ubuntu | 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 |
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