Quick answers
- Is CVE-2026-18217 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-18217 being exploited in the wild.
- How severe is CVE-2026-18217?
- Low severity, with a CVSS score of 3.4, published 31 July 2026.
- Which products and versions are affected?
- Keycloak All versions; Red Hat build of Keycloak All versions.
- Is there a fix for CVE-2026-18217?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-18217 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-18217?
- Check whether you run Keycloak or Red Hat build of Keycloak at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
A HTTP Parameter Pollution (HPP) vulnerability exists in the org.keycloak.protocol.saml package of Keycloak. The flaw occurs because the SAML HTTP-Redirect binding response preserves the full query string from the initial authentication request. If a client is configured with a wildcard redirect URI, an attacker can craft an AuthnRequest with an AssertionConsumerServiceURL containing pre-filled SAMLResponse and RelayState parameters. Keycloak then appends its legitimate parameters to the URL, resulting in duplicates. Service providers that prioritize the first occurrence of a query parameter may process the attacker's data instead of the legitimate response, enabling session swapping or login CSRF.
Affected products
- Red Hat Red Hat Build of Keycloak All versions
- Keycloak Keycloak All versions
Timeline
- 2026-07-29: disclosed: Reported via Red Hat Bugzilla
- 2026-07-31: advisory: NVD and Red Hat advisory published