CVE-2026-116372 — MISP mispguard: Feed responses with 2xx status codes other than 200 bypass filtering rules
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.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 0.4% (30-day exploitation probability)+5
- Technical severity (high)+6
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (MISP Misp-guard).
- The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Search available logs for exploit probes matching the vulnerability class (input validation), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| MISP | Misp-guard | ≤ 1.3 | Vulnerable | CVE Program (cve.org) e CISA ADP |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 7.7 | CVSS 4.0 | High | — | — | 5a6e4751-2f3f-4070-9419-94fb35b644e8 via NIST National Vulnerability Database |
| 7.7 | CVSS 4.0 | High | — | — | CIRCL via CVE Program (cve.org) e CISA ADP |
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X (score shown at the top: 5a6e4751-2f3f-4070-9419-94fb35b644e8) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
EPSS over time FIRST
Oct 26, 2026 → Oct 30, 2026 · 5 reading(s) · max 0.36%
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Timeline
What happened to this CVE, newest first.
- 2026
- Source status changed · Received → Deferred
- Affected products added · misp/misp-guard
- Record published
- CVSS changed · 7.7
- Source status changed · → Received
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× References added · Oct 26, 2026 – Oct 26, 2026
- 1× Official description updated · Oct 26, 2026 – Oct 26, 2026
References
1 on the record
Elsewhere on this site
Related CVEs (same products)
- Medium CVE-2026-118173 MISP Guard Incomplete Tag Validation Allows Non-Allowed Taxonomy Tags to Bypass Feed Policy Enforcement 4d
- High CVE-2026-116469 MISP Guard Case-Sensitive Policy Bypass Allows Unauthorized Feed Data Forwarding 5d
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No fixed version, patch or mitigation documented.
- No CISA SSVC assessment.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-116372 is "MISP mispguard: Feed responses with 2xx status codes other than 200 bypass filtering rules", rated High. It affects Misp-guard (MISP); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.7 describes technical severity. EPSS 0.36% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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