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CVE-2026-104259

5.4 mediumEPSS 0.2%

Medium (5.4) in owasp-modsecurity modsecurity. EPSS 0.2% estimated probability of exploitation activity in the next 30 days.

On this page
ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. Prior to 2.9.15 and 3.0.17, msre_fn_removeComments_execute in apache2/re_tfns.c and inplace() in src/actions/transformations/remove_comments.cc implement t:removeComments by copying the character immediately after a comment terminator without re-evaluating it. Adjacent comments can therefore leave a later comment in the transformed value, allowing inline-comment obfuscation to bypass rules that depend on comment stripping. When a comment terminator is the final content, the same copy reads one byte beyond the input buffer. This issue is fixed in versions 2.9.15 and 3.0.17.

Severity

CVSS 3.1

5.4 medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N
EPSS
0.2% estimated probability of exploitation activity in the next 30 days; 13th percentile. Scored 2026-11-10. A forecast for this CVE across the internet, not for your own systems.
CWE
CWE-670 Always-Incorrect Control Flow Implementation
Published
Assigned by
GitHub_M (CNA)
NVD analysis
Not in the NVD yet
Record from
the CVE List, synced

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Affected

Versions

From the CNA's record in the CVE List.

ProductAffected
owasp-modsecurity ModSecurity< 2.9.15
owasp-modsecurity ModSecurity>= 3.0.0, < 3.0.17

Linux distributions

DistributionReleasePackageFixed inAdvisory
Debian12, 13, 14modsecurity, modsecurity-apacheno fix listedDEBIAN-CVE-2026-104259
Ubuntu20.04:LTS, 22.04:LTS, 24.04:LTSmodsecurityno fix listedUBUNTU-CVE-2026-104259
Ubuntu26.04:LTS, 26.10modsecurity, modsecurity-apacheno fix listedUBUNTU-CVE-2026-104259
UbuntuPro:14.04:LTS, Pro:16.04:LTS, Pro:18.04:LTS and 3 moremodsecurity-apacheno fix listedUBUNTU-CVE-2026-104259

From the distributions' data via OSV.dev: the Debian Security Tracker; Ubuntu Security Notices © Canonical Ltd., CC BY-SA 4.0. Modified: reformatted and linked to CVE records. Credits. On the distributions' own pages: Debian · Ubuntu.

References

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