CVE-2021-33193

Published: Aug 16, 2021Modified: Jun 17, 2026

7.5

Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Exploitability: 3.9 / Impact: 3.6

Source: NVD

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.

Affected (7)

Products: Debian: Debian Linux · Apache: Http Server · Fedoraproject: Fedora · +2 more

Show all products

Debian: Debian Linux · Apache: Http Server · Fedoraproject: Fedora · Tenable: Tenable.sc · Oracle: Secure Backup, Zfs Storage Appliance Kit

1 product

1 product

1 product

1 product

2 products

Zfs Storage Appliance Kit

Configuration A

1 vulnerable

Vulnerable Software	Affected Versions
Debian Debian Linux	Version 10.0

Configuration B

1 vulnerable

Vulnerable Software	Affected Versions
Apache Http Server	From 2.4.17 to 2.4.49

Configuration C

2 vulnerable

Vulnerable Software	Affected Versions
Fedoraproject Fedora	Version 34
Fedoraproject Fedora	Version 35

Configuration D

1 vulnerable

Vulnerable Software	Affected Versions
Tenable Tenable.sc	Up to 5.19.1

Configuration E

2 vulnerable

Vulnerable Software	Affected Versions
Oracle Secure Backup	Before 18.1.0.1.0
Oracle Zfs Storage Appliance Kit	Version 8.8

References (26)

https://github.com/apache/httpd/commit/ecebcc035ccd8d0e2984fe41420d9e944f456b3c.patch

Source: security@apache.org

Patch

https://lists.apache.org/thread.html/re4162adc051c1a0a79e7a24093f3776373e8733abaff57253fef341d%40%3Ccvs.httpd.apache.org%3E

Source: security@apache.org

Patch

https://lists.apache.org/thread.html/ree7519d71415ecdd170ff1889cab552d71758d2ba2904a17ded21a70%40%3Ccvs.httpd.apache.org%3E

Source: security@apache.org

Patch

https://lists.debian.org/debian-lts-announce/2023/03/msg00002.html

Source: security@apache.org

Mailing ListThird Party Advisory

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DSM6UWQICBJ2TU727RENU3HBKEAFLT6T/

Source: security@apache.org

Third Party Advisory

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EUVJVRJRBW5QVX4OY3NOHZDQ3B3YOTSG/

Source: security@apache.org

Third Party Advisory

https://portswigger.net/research/http2

Source: security@apache.org

ExploitThird Party Advisory

https://security.gentoo.org/glsa/202208-20

Source: security@apache.org

Third Party Advisory

https://security.netapp.com/advisory/ntap-20210917-0004/

Source: security@apache.org

Third Party Advisory

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-2.4.49-VWL69sWQ

Source: security@apache.org

Third Party Advisory

https://www.oracle.com/security-alerts/cpuapr2022.html

Source: security@apache.org

PatchThird Party Advisory

https://www.oracle.com/security-alerts/cpujan2022.html

Source: security@apache.org

PatchThird Party Advisory

https://www.tenable.com/security/tns-2021-17

Source: security@apache.org

Third Party Advisory

https://github.com/apache/httpd/commit/ecebcc035ccd8d0e2984fe41420d9e944f456b3c.patch