CVE-2026-9084 Details
Description
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.
A vulnerability in MISP's OpenID Connect (OIDC) authentication plugin allows for automatic linking of an OIDC identity to an existing local user account, based on the email claim. This issue arises when the local account lacks a stored 'sub' value. In scenarios with insecure or untrusted Identity Provider (IdP) configurations, where email ownership is not verified, an attacker with a valid OIDC token could impersonate a victim by asserting their email address, leading to unauthorized access to the victim's account.
Users can disable the email linking feature by setting 'OidcAuth.allow_email_linking' to false. If the feature is enabled, it's recommended to ensure that the IdP verifies email ownership and to require that the 'email_verified' claim is true before linking OIDC identities to local accounts.
Metrics
CVSS 4.0 Severity and Vector Strings:
CVSS 3.x Severity and Vector Strings:
No CVSS 3.x data is available for this CVE.
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed May 20, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/MISP/MISP/commit/71f5662c1b5886613d2cd5c72fd93bb4ca6fa172 | CIRCL |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-287 | Improper Authentication | CIRCL |
Affected Products
No affected product data is available for this CVE.
Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 23, 2026 | CVE Translated | [email protected] |
| Jun 17, 2026 | CVE Modified | CIRCL |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| May 20, 2026 | New CVE Received | CIRCL |