Description
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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Red Hat | Red Hat build of Keycloak 26.4 | — | — |
| Red Hat | Red Hat build of Keycloak 26.4.14 | — | — |
| Red Hat | Red Hat build of Keycloak 26.6 | — | — |
| Red Hat | Red Hat build of Keycloak 26.6.5 | — | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | keycloak-26.5 +2 | No fix yet | — |
| Wolfi rolling | keycloak-26.6 +1 | 26.6.6-r0 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Maven | org.keycloak:keycloak-services | <= 26.6.4 | — | GHSA-p3v8-fm5p-v84h |
Advisories 1
- WID-SEC-2026-1708 Keycloak: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 8, 2026
References
- RHSA-2026:50846 vendor-advisory
- RHSA-2026:50847 vendor-advisory
- RHSA-2026:50848 vendor-advisory
- RHSA-2026:50849 vendor-advisory
- https://access.redhat.com/security/cve/CVE-2026-9793 vdb-entry
- RHBZ#2482460 issue-tracking