OWASP ModSecurity up to 2.9.14/3.0.16 htmlEntityDecode input validation

Summaryinfo

A vulnerability described as critical has been identified in OWASP ModSecurity ModSecurity up to 2.9.14/3.0.16. Affected is an unknown function of the component htmlEntityDecode. The manipulation results in input validation. This vulnerability is known as CVE-2026-61812. It is possible to launch the attack remotely. No exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in OWASP ModSecurity ModSecurity up to 2.9.14/3.0.16. It has been classified as critical. Affected is an unknown code block of the component htmlEntityDecode. The manipulation with an unknown input leads to a input validation vulnerability. CWE is classifying the issue as CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. Prior to 2.9.15 and 3.0.17, t:htmlEntityDecode recognizes only a small subset of named HTML entities, so rules that depend on the transformation can inspect different bytes than a browser or backend. Attackers can encode ASCII separators and operators with unhandled entity names, including aliases, to bypass rules that depend on the transformation. The v3 decoder also accepts prefix matches instead of requiring an exact entity-token length, which can transform invalid longer names into different bytes. This issue is fixed in versions 2.9.15 and 3.0.17.

The advisory is available at github.com. This vulnerability is traded as CVE-2026-61812 since 07/10/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. The technical details are unknown and an exploit is not available.

Upgrading to version 2.9.15 or 3.0.17 eliminates this vulnerability.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Vendor

• OWASP ModSecurity

Name

• ModSecurity

Version

• 2.9.0
• 2.9.1
• 2.9.2
• 2.9.3
• 2.9.4
• 2.9.5
• 2.9.6
• 2.9.7
• 2.9.8
• 2.9.9
• 2.9.10
• 2.9.11
• 2.9.12
• 2.9.13
• 2.9.14
• 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

• 🔒
• 🔒
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CPE 2.2info

• 🔒
• 🔒
• 🔒

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If you want to get best quality of vulnerability data, you may have to visit VulDB.

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