🛡️ CVE-2021-33193 — apache

🟠 CVSS 8.0 — High ✅ No Known Exploit OSV
8.0
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Request splitting via HTTP/2 method injection and mod_proxy

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.

Affected software

CVE-2021-33193 is recorded against 1 package.

  • apache

Timeline and source

Published on 6 March 2024 and last revised on 20 May 2025. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

github.com (Web)
lists.apache.org (Web)
lists.apache.org (Web)
lists.debian.org (Web)
lists.fedoraproject.org (Web)
lists.fedoraproject.org (Web)
portswigger.net (Web)
security.gentoo.org (Web)
security.netapp.com (Web)
tools.cisco.com (Web)
www.oracle.com (Web)
www.oracle.com (Web)
www.tenable.com (Web)
nvd.nist.gov (Web)

CVE-2021-33193 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity HIGH
CVSS Score 8.0
CVSS Vector N/A
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2024-03-06
Updated 2026-08-12
Modified 2025-05-20
Fix URL N/A

Affected Packages

Software From version Fixed in
apache

References

Similar Threats

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