{"id":"CVE-2026-9793","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-9793","summary":"Keycloak has an Improper Verification of Cryptographic Signature issue","details":"A flaw was found in Keycloak. When a JSON Web Encryption (JWE) encrypted request object is submitted, Keycloak may incorrectly process unsigned claims if the decrypted content is raw JSON, bypassing the configured signature policy. This allows a remote attacker to submit unauthorized claims, leading to a compromise of data integrity within the OpenID Connect (OIDC) authorization flow. While a redirect URI allowlist acts as a compensating control, this vulnerability violates OIDC Core and Financial-grade API (FAPI) signing requirements.","published":"2026-05-28T06:31:09Z","modified":"2026-08-21T22:26:54.937262576Z","cvss":{"score":5.9,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N"},"epss":{"score":0.00163,"percentile":0.05719,"asOf":"2026-08-24"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Maven","name":"org.keycloak:keycloak-services","fixedVersion":null}],"fix":null,"references":[{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-9793"},{"type":"WEB","url":"https://github.com/keycloak/keycloak/issues/49429"},{"type":"WEB","url":"https://access.redhat.com/errata/RHSA-2026:50846"},{"type":"WEB","url":"https://access.redhat.com/errata/RHSA-2026:50847"},{"type":"WEB","url":"https://access.redhat.com/errata/RHSA-2026:50848"},{"type":"WEB","url":"https://access.redhat.com/errata/RHSA-2026:50849"},{"type":"WEB","url":"https://access.redhat.com/security/cve/CVE-2026-9793"},{"type":"WEB","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2482460"},{"type":"PACKAGE","url":"https://github.com/keycloak/keycloak"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-21T22:26:54.937262576Z"}}