CVE-2026-82843 WP OAuth Server < 6.4.0 - Subscriber+ Cross-User Account Takeover via OIDC ID Token Substitution
Subscribers can impersonate administrators by exploiting OIDC token substitution flaws in the WP OAuth Server plugin, leading to full account takeover.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-82843?
CVE-2026-82843 is a critical authentication bypass vulnerability in Unknown WP OAuth Server ( Login with WordPress ), published on 23 Sep 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
The WP OAuth Server ( Login with WordPress ) WordPress plugin before 6.4.0 does not bind the OpenID Connect identity assertion it issues to the authorization grant being exchanged, returning instead the assertion belonging to whichever user authenticated most recently, which allows users with the Subscriber role and above to obtain a validly signed identity assertion for another user, including an administrator, and authenticate as them at any application that uses the site for single sign-on.
Weakness: CWE-287
Which versions are affected by CVE-2026-82843?
How do I fix CVE-2026-82843?
No fix has been published for CVE-2026-82843 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-2026-82843 being exploited?
There is no known exploitation of CVE-2026-82843 in the wild and no public exploit code.
Sources
Also known as GHSA-rwfr-37x7-2rr8.