MISP contains a session fixation vulnerability in the CustomAuth authentication (a custom configuration) flow. When a user was successfully authenticated through CustomAuth, MISP stored the authenticated user identity in the existing session without first rotating the session identifier.
As a result, if an attacker can cause a victim to use a session identifier known to the attacker before authentication, that same session identifier remains valid after the victim successfully authenticates. The attacker could subsequently reuse the fixed session identifier to access the victim's authenticated MISP session, potentially gaining the privileges associated with the victim's account.
The issue occurs because __customAuthentication() wrote the authenticated user into the existing CakePHP session while the call to Session->renew() had previously been disabled. The patch restores session identifier rotation when a new authentication occurs or when the authenticated user changes, while avoiding unnecessary session renewal on every request.
As a result, if an attacker can cause a victim to use a session identifier known to the attacker before authentication, that same session identifier remains valid after the victim successfully authenticates. The attacker could subsequently reuse the fixed session identifier to access the victim's authenticated MISP session, potentially gaining the privileges associated with the victim's account.
The issue occurs because __customAuthentication() wrote the authenticated user into the existing CakePHP session while the call to Session->renew() had previously been disabled. The patch restores session identifier rotation when a new authentication occurs or when the authenticated user changes, while avoiding unnecessary session renewal on every request.
Metrics
Affected Vendors & Products
Advisories
No advisories yet.
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
| Link | Providers |
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| https://github.com/MISP/MISP/commit/e2eb2f058 |
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History
Thu, 03 Sep 2026 17:15:00 +0000
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Misp
Misp misp |
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| Vendors & Products |
Misp
Misp misp |
Thu, 03 Sep 2026 15:45:00 +0000
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| Description | MISP contains a session fixation vulnerability in the CustomAuth authentication (a custom configuration) flow. When a user was successfully authenticated through CustomAuth, MISP stored the authenticated user identity in the existing session without first rotating the session identifier. As a result, if an attacker can cause a victim to use a session identifier known to the attacker before authentication, that same session identifier remains valid after the victim successfully authenticates. The attacker could subsequently reuse the fixed session identifier to access the victim's authenticated MISP session, potentially gaining the privileges associated with the victim's account. The issue occurs because __customAuthentication() wrote the authenticated user into the existing CakePHP session while the call to Session->renew() had previously been disabled. The patch restores session identifier rotation when a new authentication occurs or when the authenticated user changes, while avoiding unnecessary session renewal on every request. | |
| Title | Session Fixation in MISP CustomAuth Authentication Allows Session Hijacking | |
| Weaknesses | CWE-384 | |
| References |
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| Metrics |
cvssV4_0
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Projects
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Status: PUBLISHED
Assigner: CIRCL
Published:
Updated: 2026-09-03T15:43:12.832Z
Reserved: 2026-09-03T15:29:58.290Z
Link: CVE-2026-85238
No data.
Status : Undergoing Analysis
Published: 2026-09-03T16:18:27.313
Modified: 2026-09-03T16:45:08.223
Link: CVE-2026-85238
No data.
OpenCVE Enrichment
Updated: 2026-09-03T17:00:06Z
Weaknesses