OWASP ModSecurity up to 3.0.16 Response Body Inspection src/transaction.cc information disclosure

Summaryinfo

A vulnerability has been found in OWASP ModSecurity up to 3.0.16 and classified as problematic. This vulnerability affects unknown code of the file src/transaction.cc of the component Response Body Inspection. Performing a manipulation results in information disclosure. This vulnerability is identified as CVE-2026-73856. The attack can be initiated remotely. There is not any exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in OWASP ModSecurity up to 3.0.16. It has been classified as problematic. This affects an unknown part of the file src/transaction.cc of the component Response Body Inspection. The manipulation with an unknown input leads to a information disclosure vulnerability. CWE is classifying the issue as CWE-200. The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. This is going to have an impact on confidentiality. The summary by CVE is:

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.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-73856 since 08/13/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1592 according to MITRE ATT&CK.

Upgrading to version 3.0.17 eliminates this vulnerability.

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Productinfo

Vendor

• OWASP

Name

• ModSecurity

Version

• 3.0.0
• 3.0.1
• 3.0.2
• 3.0.3
• 3.0.4
• 3.0.5
• 3.0.6
• 3.0.7
• 3.0.8
• 3.0.9
• 3.0.10
• 3.0.11
• 3.0.12
• 3.0.13
• 3.0.14
• 3.0.15
• 3.0.16

License

• open-source

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

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