CVE-2021-35368

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.7% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-11-05 · updated 2026-06-17

Description

OWASP ModSecurity Core Rule Set 3.1.x before 3.1.2, 3.2.x before 3.2.1, and 3.3.x before 3.3.2 is affected by a Request Body Bypass via a trailing pathname.

Affected products

Debian Linux: 10.0
Fedoraproject Fedora: 36, 37
coreruleset: from 3.1.0 before 3.1.2; from 3.2.0 before 3.2.1; from 3.3.0 before 3.3.2 — fixed in 3.1.2, 3.2.1, 3.3.2

How to fix

Upgrade to a fixed version: coreruleset 3.1.2, 3.2.1, 3.3.2. Check the vendor advisory for mitigations.

References

https://coreruleset.org/20210630/cve-2021-35368-crs-request-body-bypass/
https://lists.debian.org/debian-lts-announce/2023/01/msg00033.html
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6MS5GMNYHFFIBWLJW7N3XAD24SLF3PFZ/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IVYUJOKHDEXFTM2CZMEESJ6TZSPVNSSZ/
https://owasp.org/www-project-modsecurity-core-rule-set/
https://portswigger.net/daily-swig/lessons-learned-how-a-severe-vulnerability-in-the-owasp-modsecurity-core-rule-set-sparked-much-needed-change
https://portswigger.net/daily-swig/waf-bypass-severe-owasp-modsecurity-core-rule-set-bug-was-present-for-several-years
https://security.gentoo.org/glsa/202305-25
https://coreruleset.org/20210630/cve-2021-35368-crs-request-body-bypass/
https://lists.debian.org/debian-lts-announce/2023/01/msg00033.html
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6MS5GMNYHFFIBWLJW7N3XAD24SLF3PFZ/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IVYUJOKHDEXFTM2CZMEESJ6TZSPVNSSZ/

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