MISP OIDC authentication bypass via automatic email-based account linking under insecure IdP configurations
Key facts
- Attack vector
- Adjacent network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- High
- Attack requirements
- Present
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- High · None · None
- Fix status
- No fix listed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-287.
Summary
MISP’s OIDC authentication plugin allowed automatic linking of an OIDC identity to an existing local user account based on the email claim when the local account had no stored sub value. Under insecure or untrusted IdP configurations where email ownership is not enforced, an attacker with a valid OIDC token could assert a victim’s email address and authenticate as that user, leading to account takeover.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| MISP | misp | 2.5.0 – 2.5.37 | — | No fix listed | CNA |
- misp VendorMISP Affected 2.5.0 – 2.5.37 Fixed in — No fix listed CNA
CPE names Threatist (inferred) · 1
Inferred from how NVD named this product before; not given by a source.
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:misp-project:misp:*:*:*:*:*:*:*:* | — | — | Misp-project |
- cpe:2.3:a:misp-project:misp:*:*:*:*:*:*:*:* Versions — — ·Misp-project
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2026-9084
- 2026-10-03 Alias added: GHSA-5895-8h7c-2833
More MISP vulnerabilities
- TI-2025-41517 In MISP before 2.5.28, app/View/Elements/Workflows/executionPath.ctp allows XSS in the workflow execution path. CVSS 3.1CRITICAL 9.0
- TI-2026-65744 MISP TOTP Code Replay Allows Duplicate Authentication Within Validity Period CVSS 4.0CRITICAL 9.3
- TI-2026-54145 Path Traversal in MISP Object Template Resolution During STIX Import and Export in misp-stix library CVSS 4.0HIGH 8.8
- TI-2020-10250 MISP MISP-maltego 1.4.4 incorrectly shares a MISP connection across users in a remote-transform use case. CVSS 3.1CRITICAL 9.8
- TI-2026-59159 MISP Unauthenticated Mail Endpoints Allow Unbounded Storage Consumption and Request Flooding CVSS 4.0HIGH 8.7
- TI-2026-58541 MISP LDAP and LinOTP Authentication Bypass via Empty or Invalid Credentials CVSS 4.0CRITICAL 9.5
Sources
- CVE-2026-9084 · CVE Program
- CVE-2026-9084 · NVD
- FIRST EPSS
- GHSA-5895-8h7c-2833 · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences