Vulnerability · Published May 20, 2026 · Assigned by CIRCL
CVE-2026-9084MISP OIDC authentication bypass via automatic email-based account linking under insecure IdP configurations
Medium 6.0
In plain English
A medium-severity improper authentication in misp from misp. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 8% of all known vulnerabilities).
Official 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.
Affected products (as reported)
Weakness: CWE-287 · Vector: CVSS:4.0/AV:A/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N