| 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, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
| References | DLA-3351-1 |
Vulnerable and fixed packages
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|
| apache2 (PTS) | jessie, jessie (lts) | 2.4.10-10+deb8u25 | fixed |
| stretch (security) | 2.4.25-3+deb9u13 | vulnerable |
| stretch (lts), stretch | 2.4.25-3+deb9u15 | vulnerable |
| buster | 2.4.38-3+deb10u8 | vulnerable |
| buster (security) | 2.4.38-3+deb10u10 | fixed |
| bullseye | 2.4.56-1~deb11u2 | fixed |
| bullseye (security) | 2.4.59-1~deb11u1 | fixed |
| bookworm | 2.4.57-2 | fixed |
| bookworm (security) | 2.4.59-1~deb12u1 | fixed |
| trixie | 2.4.58-1 | fixed |
| sid | 2.4.59-1 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|
| apache2 | source | jessie | (not affected) | | | |
| apache2 | source | buster | 2.4.38-3+deb10u9 | | DLA-3351-1 | |
| apache2 | source | bullseye | 2.4.48-3.1+deb11u1 | | | |
| apache2 | source | (unstable) | 2.4.48-4 | | | |
Notes
[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 (2.4.49)
https://httpd.apache.org/security/vulnerabilities_24.html#CVE-2021-33193
https://git.centos.org/rpms/httpd/blob/c496dea5e0b6e82a9f503e973fc5d5ea93a94180/f/SOURCES/httpd-2.4.37-CVE-2021-33193.patch (2.4.37)
http://launchpadlibrarian.net/559974735/apache2_2.4.29-1ubuntu4.16_2.4.29-1ubuntu4.17.diff.gz (2.4.29)
[jessie] - apache2 <not-affected> (HTTP/2 support introduced in 2.4.17)