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.
Conclusion & alert: CVE-2025-9485 is rated Moderate Risk (62.9/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 0.55%). Mandatory action: Review affected assets and schedule remediation.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-05-10 | 0.65% | 0.55% | -0.10% |
| 2 | 2026-03-04 | 0.17% | 0.65% | +0.48% |
| 3 | 2026-03-03 | — | 0.17% | — |
Full EPSS history (19 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 9.8 | 3.1 | CRITICAL |
|
3.9 | 5.9 | [email protected] |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| No affected products in dataset. | |||