OAuth Single Sign On – SSO (OAuth Client): A security weakness
OAuth Single Sign On – SSO (OAuth Client) is affected by a security weakness. The vulnerable path is reachable without authentication. The resulting impact depends on how the affected component exposes the vulnerable operation.
- Component
- OAuth Single Sign On – SSO (OAuth Client)
- Affected
- See vendor advisory
- Safe version
- See mitigation notes
- Published
- Oct 04, 2025
This CVE was published Oct 04, 2025 and is one of 5 known issues for this plugin.
Update, patch or deactivate.
Update OAuth Single Sign On – SSO (OAuth Client) to a release outside the affected range, or disable and remove it until a fixed version is available.
No confirmed safe version is listed. Consider a vendor-supported patch or temporarily restricting the affected functionality while you assess the risk.
Deactivate only when warranted by your risk profile, or when advised by your hosting provider in the limited circumstances where the vulnerability cannot otherwise be mitigated. If you’re unsure which action is appropriate, contact Fused or your hosting provider for guidance.
Technical description
The OAuth Single Sign On – SSO (OAuth Client) plugin for WordPress is vulnerable to Improper Verification of Cryptographic Signature in versions up to, and including, 6.26.12. This is due to the plugin performing unsafe JWT token processing without verification or validation in the `get_resource_owner_from_id_token` function. This makes it possible for unauthenticated attackers to bypass authentication and gain access to any existing user account - including administrators in certain configurations - or to create arbitrary subscriber-level accounts.
CVE / CNA vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H