CVE-2026-89058
A flaw was found in RESTEasy's CorsFilter, which, when configured to allow all origins ("*"), reflects the request's Origin header back in the Access-Control-Allow-Origin response together with Access-Control-Allow-Credentials: true. This permissive cross-origin policy allows a malicious website to make credentialed cross-origin requests and read authenticated responses from a victim's session, resulting in a loss of confidentiality.
- Published Sep 18, 2026
- CVSS 7.4 high
- 0.5% chance of exploitation in the next 30 days (EPSS)
- A fix is available