| Name | CVE-2026-33523 |
| Description | HTTP response splitting vulnerability in multiple Apache HTTP Server modules with untrusted or compromised backend servers. This issue affects Apache HTTP Server: from through 2.4.66. Users are recommended to upgrade to version 2.4.67, which fixes the issue. |
| Source | CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
| Debian Bugs | 1135737 |
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|---|---|---|
| apache2 (PTS) | bullseye | 2.4.62-1~deb11u1 | vulnerable |
| bullseye (security) | 2.4.66-1~deb11u1 | vulnerable | |
| bookworm | 2.4.66-1~deb12u1 | vulnerable | |
| bookworm (security) | 2.4.62-1~deb12u2 | vulnerable | |
| trixie | 2.4.66-1~deb13u2 | vulnerable | |
| forky, sid | 2.4.66-8 | vulnerable |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|---|---|---|---|---|---|
| apache2 | source | (unstable) | 2.4.67-1 | 1135737 |
https://www.openwall.com/lists/oss-security/2026/05/04/23
https://httpd.apache.org/security/vulnerabilities_24.html#CVE-2026-33523
https://github.com/apache/httpd/commit/0218d4b9c1c0706df4bd7a3e3b15f71d4b66126a (2.4.67-rc1-candidate)