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20Track

keycloak-services: saml redirect binding signature bypass via percent-encoded parameter names

Red Hat · CVE-2026-117691 ETK-2026-3628 EUVD-2026-117441 GHSA-C85J-3HQ2-Q6WJ
0 news outlets1 CERTs and agencies0 research labs

Assessment: Track

SSVC decision points: exploitation none, automatable yes, technical impact total, deployment low.

What is it?

A flaw was found in the SAML HTTP-Redirect binding implementation of Keycloak. The issue occurs because the server processes percent-encoded parameter names (like %53AMLResponse) while the signature verification logic only checks literal parameter names. An attacker can use this discrepancy to provide a crafted, unsigned SAML message that the server processes instead of a legitimately signed one, leading to full account takeover of federated users.

Evidence

Official warnings1National CERTs, government cyber security agencies and the vendor’s own advisories

Exploitation

  • Exploit code published (not verified by us)
  • Exploited in the wild (confirmed by a source)
  • Listed as known exploited (CISA KEV)
CVSS
9.1
EPSS
0.3%
First seen
5 d ago
Status
confirmed

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