CVE-2026-116372: MISP mispguard: Feed responses with 2xx status codes other than 200 bypass filtering rules

DescriptionCVE.org

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.

• MISP · misp-guardup to and including 1.3

Exploitation

Unlikely (under 1%). EPSS under 1%, or no score yet.

CISA KEV

Not listed

Public check

No public nuclei template

Weakness

Improper Input Validation · Input Validation and Logic

Vendor

MISP

Published

October 2026

Band

Unlikely (under 1%), October 2026

• NVD entrynvd.nist.gov
• CVE recordcve.org
• Weakness CWE-20cwe.mitre.org
• Patchgithub.com