CVE-2026-73856

CVSS 8.6 (high) · published 2026-11-05

ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. From 3.0.0 until 3.0.17, src/transaction.cc compares a response Content-Type value against SecResponseBodyMimeType entries case-sensitively. A mixed-case response media type that is semantically equivalent to a configured lowercase type can therefore be treated as unconfigured, causing ModSecurity to skip RESPONSE_BODY inspection. An unauthenticated requester can then receive response content that a phase 4 rule would otherwise block, including sensitive error or debug data. This issue is fixed in version 3.0.17.

Weakness: CWE-178

Source: NVD CVE-2026-73856

References

• https://github.com/owasp-modsecurity/ModSecurity/commit/23ccd9202114f8313df3773f7992782fd9949c98
• https://github.com/owasp-modsecurity/ModSecurity/releases/tag/v3.0.17
• https://github.com/owasp-modsecurity/ModSecurity/security/advisories/GHSA-vmg8-j66p-vgvw
• https://github.com/owasp-modsecurity/ModSecurity/security/advisories/GHSA-vmg8-j66p-vgvw

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