CVE-2026-9084 MISP OIDC authentication bypass via automatic email-based account linking under insecure IdP configurations
Attackers can hijack MISP accounts by exploiting OIDC email-based linking when IdP email verification is disabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-9084?
CVE-2026-9084 is a medium-severity authentication bypass vulnerability in misp, published on 20 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
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.
Weakness: CWE-287
Which versions are affected by CVE-2026-9084?
How do I fix CVE-2026-9084?
No fix has been published for CVE-2026-9084 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-9084 being exploited?
There is no known exploitation of CVE-2026-9084 in the wild and no public exploit code.
Sources
Also known as GHSA-5895-8h7c-2833.