MISP Guard up to 1.3 Feed Response Evaluation src/mispguard.py process_feed_response input validation

Summaryinfo

A vulnerability described as critical has been identified in MISP Guard up to 1.3. This affects the function process_feed_response of the file src/mispguard.py of the component Feed Response Evaluation. Executing a manipulation can lead to input validation. This vulnerability is registered as CVE-2026-116372. It is possible to launch the attack remotely. No exploit is available. It is advisable to implement a patch to correct this issue.

Detailsinfo

A vulnerability classified as critical was found in MISP Guard up to 1.3. This vulnerability affects the function process_feed_response of the file src/mispguard.py of the component Feed Response Evaluation. The manipulation with an unknown input leads to a input validation vulnerability. The CWE definition for the vulnerability is 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. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

MISP mispguard is a security filtering proxy that inspects and blocks MISP feed responses based on configured rules. The process_feed_response method in src/mispguard.py was responsible for evaluating feed responses before they reached the MISP instance. The original logic only explicitly handled the case where the HTTP status code was not 200 by passing the response through without filtering, on the assumption that non-200 responses would not carry ingestible event data. However, HTTP 2xx status codes other than 200 (such as 201 Created, 203 Non-Authoritative Information, and 206 Partial Content) were also passed through unfiltered. Because MISP may still ingest content from these responses, a malicious or compromised feed host could return a 203 or 206 status code with arbitrary content, effectively bypassing all of mispguard's filtering rules. This allowed unfiltered or malicious feed data to be ingested into the MISP instance, undermining the security controls that mispguard is designed to enforce. The vulnerability requires the attacker to control or compromise a feed endpoint configured in the MISP instance. No authentication or user interaction is required beyond the feed polling mechanism already in place.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-116372 since 10/26/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available.

Applying the patch b5f606a4e57a49cc4dbf9b3ef0c6ddd19f866735 is able to eliminate this problem.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

• MISP

Name

• Guard

Version

• 1.0
• 1.1
• 1.2
• 1.3

License

• open-source

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CPE 2.2info

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