What’s Vulnerable › Vulnerabilities

CVE-2026-52761: ModSecurity: Transformation utf8toUnicode produces wrong output on i386 architecture

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-10 · updated 2026-10-25
• Weakness: CWE-467

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.

Affected products

• owasp-modsecurity ModSecurity: from 3.0.0 through 3.0.15

References

• https://github.com/owasp-modsecurity/ModSecurity/commit/edcd010814e234d46e2ec55a0f1078ff9d3032e4
• https://github.com/owasp-modsecurity/ModSecurity/releases/tag/v3.0.16
• https://github.com/owasp-modsecurity/ModSecurity/security/advisories/GHSA-qjgm-7gp4-f8qq

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