Vulnerability in Red Hat

[ Why it matters ]Priority signals

• Public proof-of-concept exploit exists (CISA SSVC)

[ Description ]Official description

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.

[ Fixes ]Fixes and patches

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ Advisories ]Government CERT advisories

• BSI CERT-Bund19 Oct 2026WID-SEC-2026-4029

  Red Hat Enterprise Linux (python-tornado, resteasy-core, bubblewrap, pgvector): Multiple vulnerabilities Translated from German

  Risk highCVE-2026-89059CVE-2026-82397CVE-2026-87766+3 more CVEs

[ References ]References

• access.redhat.com/errata/RHSA-2026:83082vendor-advisoryx_refsource_REDHAT
• access.redhat.com/errata/RHSA-2026:83520vendor-advisoryx_refsource_REDHAT
• access.redhat.com/errata/RHSA-2026:85234vendor-advisoryx_refsource_REDHAT
• access.redhat.com/security/cve/CVE-2026-89058vdb-entryx_refsource_REDHAT
• bugzilla.redhat.com/show_bug.cgiissue-trackingx_refsource_REDHAT
• github.com/resteasy/resteasy/commit/efeb2b7
• github.com/resteasy/resteasy/security/advisories/GHSA-972r-f3fv-whm3