cvedb.io
CVE-2026-18209
LOW · CVSS 3.4
EPSS exploitation probability: 0%
Published 2026-07-31T08:16:27.467 · Last modified 2026-07-31T08:16:27.467

Summary

A flaw was found in the keycloak-services component of Keycloak, which handles OpenID Connect (OIDC) authentication flows. The issue occurs because the security check designed to prevent HTTP parameter pollution only inspects the query portion of a redirect URL and ignores the fragment portion. When a client is configured with a wildcard redirect URI, an attacker can use this to inject duplicate security parameters into the login response. If a client application is not configured correctly, it might trust the attacker's injected data instead of the real security information from Keycloak, leading to session fixation or account confusion.

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.