CVE-2026-9084: MISP OIDC authentication bypass via automatic email-based account linking under insecure IdP configurations
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 Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-9084?
CVE-2026-9084 has a medium severity rating of 6 based on the CVSS scoring.
How do I fix CVE-2026-9084?
To fix CVE-2026-9084, ensure that email ownership is enforced in your IdP configurations to prevent automatic linking.
What type of vulnerability is CVE-2026-9084?
CVE-2026-9084 is an authentication bypass vulnerability related to automatic email-based account linking.
Who is affected by CVE-2026-9084?
CVE-2026-9084 affects users of the MISP OIDC authentication plugin under insecure IdP configurations.
What should I do if I suspect an exploit of CVE-2026-9084?
If you suspect an exploit of CVE-2026-9084, immediately review your IdP configurations and perform an audit of user accounts.