CVE-2026-118173
MISP Guard Incomplete Tag Validation Allows Non-Allowed Taxonomy Tags to Bypass Feed Policy Enforcement
02 Description
MISP Guard Incomplete Tag Validation Allows Non-Allowed Taxonomy Tags to Bypass Feed Policy Enforcement
03 Exploitation and scoring
- Exploitation
- Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.
- SSVC decision
- Not assessed by CISA
- EPSS probability
- 0.30% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 22.6% of scored records. A rank, not a probability.
- NVD base score
- 6.1 (CVSS v4.0), scored by the NVD independently of the CNA.
- NVD CVSS vector
- CVSS:4.0/AV:N/AC:L/AT:N/PR:H/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
- NVD analysis status
- Deferred. NVD last modified this record on 2026-10-28.
- Red Hat severity
- No Red Hat rating. Red Hat rates the CVEs that affect its products.
Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.
04 Metadata
- Published
- 2026-10-27 18:11Z1 DAY AGO
- Last updated
- 2026-10-27 18:11Z1 DAY AGO
- Reserved
- 2026-10-27
- Assigning CNA
- CIRCL
- Record state
- PUBLISHED
- Severity
- Medium (CVSS 6.1)
- CNA CVSS vector
- CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:N/SC:N/SI:H/SA:N
- Weaknesses
- Data version
- 5.2
- Document digest
- 3155f888050c3d89e42f01a86849d976d42d57a457bd68cdbc45553dec026232
05 Affected products
06 References
- github.comSecurity patchhttps://github.com/MISP/misp-guard/commit/6127d94c350e4dfe31fd4426ba26f51294ed3867
07 Remediation
The fix introduces a new validation function, check_required_taxonomy_tags_allowed, that iterates over every tag belonging to a required taxonomy and verifies each one is present in the configured allowed-tags list, raising a ForbiddenException if any tag is not allowed. This check is applied at both the event level and the attribute level. Additionally, an inherit_event_taxonomies flag is introduced so that attributes without their own required-taxonomy tags inherit the event's already-validated taxonomy, while attributes that do carry tags of the required taxonomy are still fully validated against the allowed list. This ensures that no non-allowed tag of a required taxonomy can pass the guard regardless of whether an allowed tag is also present.