CVE-2026-52761

Name	CVE-2026-52761
Description	ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. From 3.0.0 through 3.0.15, the t:utf8toUnicode transformation in src/actions/transformations/utf8_to_unicode.cc produces wrong output on i386 architecture because snprintf uses sizeof on a char pointer rather than the length of the unicode buffer, allowing rules that use this transformation to be bypassed on i386 architecture. This issue is fixed in version 3.0.16.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs	1141961

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
modsecurity (PTS)	bullseye	3.0.4-2	vulnerable
	bookworm	3.0.9-1+deb12u2	vulnerable
	trixie	3.0.14-1+deb13u1	vulnerable
	forky, sid	3.0.16-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
modsecurity	source	(unstable)	3.0.16-1			1141961

Notes

[trixie] - modsecurity <no-dsa> (Minor issue)
[bookworm] - modsecurity <postponed> (Minor issue; i386-only rule bypass in utf8toUnicode transform)
[bullseye] - modsecurity <postponed> (Minor issue; i386-only rule bypass in utf8toUnicode transform)
https://github.com/owasp-modsecurity/ModSecurity/security/advisories/GHSA-qjgm-7gp4-f8qq
Fixed by: https://github.com/owasp-modsecurity/ModSecurity/commit/edcd010814e234d46e2ec55a0f1078ff9d3032e4 (v3.0.16)