CVE-2026-73856

HIGH 8.6

ModSecurity: Response Body Inspection Bypass

CVSS Score

8.6

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-178
Vendor	owasp-modsecurity
Product	modsecurity
Published	Nov 5, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

None

Availability

None

Affected Versions

owasp-modsecurity / ModSecurity

>= 3.0.0, < 3.0.17

References

NVD ↗ CVE.org ↗ EPSS Data ↗

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