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Alerts This Week
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Debian: modsecurity-crs Critical Fix for CVE-2026-21876 DSA-6105-1

debian
Calendar Grey January 21, 2026
Scroller Debian
Critical advisory for modsecurity-crs in Debian mitigating improper parsing issues. Upgrade recommended for stability.
It was discovered that one of the rules in the OWASP ModSecurity Core Rule Set parsed some multipart requests incorrectly
Topics%20covered

Topics Covered

security advisory critical debian modsecurity-crs cve-2026-21876 improper parsing

Summary

For the oldstable distribution (bookworm), this problem has been fixed
in version 3.3.4-1+deb12u1.

For the stable distribution (trixie), this problem has been fixed in
version 3.3.7-1+deb13u1.

We recommend that you upgrade your modsecurity-crs packages.

For the detailed security status of modsecurity-crs please refer to
its security tracker page at:
https://security-tracker.debian.org/tracker/source-package/modsecurity-crs

Further information about Debian Security Advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://www.debian.org/security/



Severity
critical
Lowest
Low
Medium
High
Critical

Package: modsecurity-crs
CVE ID: CVE-2026-21876

Topics%20covered

Topics Covered

security advisory critical debian modsecurity-crs cve-2026-21876 improper parsing

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