| Name | CVE-2021-33193 |
| Description | A crafted method sent through HTTP/2 will bypass validation and be forwarded by mod_proxy, which can lead to request splitting or cache poisoning. This issue affects Apache HTTP Server 2.4.17 to 2.4.48. |
| Source | CVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub code/issues, web search, more) |
| NVD severity | medium |
Vulnerable and fixed packages
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|
| apache2 (PTS) | stretch | 2.4.25-3+deb9u9 | vulnerable |
| stretch (security) | 2.4.25-3+deb9u11 | vulnerable |
| buster | 2.4.38-3+deb10u5 | vulnerable |
| buster (security) | 2.4.38-3+deb10u6 | vulnerable |
| bullseye | 2.4.48-3.1+deb11u1 | fixed |
| bullseye (security) | 2.4.51-1~deb11u1 | fixed |
| bookworm, sid | 2.4.51-2 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|
| apache2 | source | bullseye | 2.4.48-3.1+deb11u1 | | | |
| apache2 | source | (unstable) | 2.4.48-4 | | | |
Notes
[buster] - apache2 <postponed> (Revisit when a suitable backport is available for 2.4.38)
[stretch] - apache2 <postponed> (Revisit when a suitable backport is available for 2.4.25)
https://portswigger.net/research/http2
https://github.com/apache/httpd/commit/ecebcc035ccd8d0e2984fe41420d9e944f456b3c
https://httpd.apache.org/security/vulnerabilities_24.html#CVE-2021-33193