Vulnerability · Published Sep 23, 2026 · Assigned by WPScan

CVE-2026-82843WP OAuth Server < 6.4.0 - Subscriber+ Cross-User Account Takeover via OIDC ID Token Substitution

Critical 9.0

In plain English

A critical-severity improper authentication in WP OAuth Server ( Login with WordPress ) from Unknown. 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 9% of all known vulnerabilities).

Severity (CVSS 3.1)9.0Critical

Exploit odds (30 days)0.2%top 91.5% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

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.

Affected products (as reported)

Vendor	Product	Versions
Unknown	WP OAuth Server ( Login with WordPress )	0 – before 6.4.0

Weakness: CWE-287 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

References

https://wpscan.com/vulnerability/45bc7096-5d04-4fe6-a332-31aed507a3a0/ exploit, vdb-entry, technical-description