A flaw was found in the SAML protocol implementation of Keycloak, an open-source identity and access management solution.
CVE-2026-18217
A flaw was found in the SAML protocol implementation of Keycloak, an open-source identity and access management solution. The issue occurs when Keycloak handles SAML authentication requests using the HTTP-Redirect binding. If a client is configured with a wildcard redirect URL, an attacker can craft a request that includes malicious parameters. When a user authenticates, Keycloak appends its legitimate response to the attacker's parameters. This can cause some service providers to process the attacker's data instead of the real login information, potentially leading to a user being logged into the wrong account.
Assessment
- CVSS
- 3.4 (v3.1)
- Severity
- Low
- EPSS
- 0.36% chance of exploitation in the next 30 days
- Known exploited
- Not listed in CISA KEV
- Exploit availability
- Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
- Published
- 31 July 2026
- Last updated
- 6 November 2026
- Affected
- Red Hat · Red Hat build of Keycloak 26.4
- Assigner
- redhat
CVSS vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:N/I:L/A:N
At the source
References
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