CVE-2026-91819
MISP: HTTP Method Override Bypasses CSRF and Form Validation in BetterSecurityComponent
02 Description
MISP: HTTP Method Override Bypasses CSRF and Form Validation in BetterSecurityComponent
03 Exploitation and scoring
- Exploitation
- Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.
- SSVC decision
- ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
- AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
- Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.
- EPSS probability
- 0.19% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 9.6% of scored records. A rank, not a probability.
- NVD base score
- 6.9 (CVSS v4.0), scored by the NVD independently of the CNA.
- NVD CVSS vector
- CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/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 2026-09-16.
- 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
- 2026-09-15 07:41Z1 MO AGO
- Last updated
- 2026-09-15 14:37Z1 MO AGO
- Reserved
- 2026-09-15
- Assigning CNA
- CIRCL
- Record state
- PUBLISHED
- Severity
- Medium (CVSS 6.9)
- CNA CVSS vector
- CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
- Weaknesses
- Data version
- 5.2
- Document digest
- e3b11012d2fcf64c04fc1548eb703e75c82cbf72b9fff8a6b977f4610cc37cd6
05 Affected products
06 References
- github.comSecurity patchhttps://github.com/MISP/MISP/commit/29af008c4
07 Remediation
The fix introduces a __rejectUnsafeMethodOverride() check in BetterSecurityComponent::startup() that executes before the parent SecurityComponent::startup() computes $hasData. It inspects both the _method POST field and the X-HTTP-Method-Override header (mirroring CakePHP's precedence) and rejects any value that is not a string in the allowed set {POST, PUT, PATCH, DELETE}. Non-string values (e.g., array payloads like _method[]=GET) are also refused. A BadRequestException is thrown and the event is logged, preventing the request from ever reaching the parent security logic with an emptied body.