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Fencer Intel
critical 9.1

CVE-2026-117691 json

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

published 4d ago modified 2d ago also EUVD-2026-117441

cvss
9.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 20%
public exploits
0
none known

Summary

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.

Patch / fix

  • Red Hat Red Hat build of Keycloak 26.6 26.6-25, 26.6-26, 26.6.9-1

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-117691 updated cvss 9.1

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

  • Red Hat build of Keycloak 26.6 rhbk/keycloak-rhel9 26.6-25, rhbk/keycloak-rhel9-operator 26.6-26, rhbk/keycloak-operator-bundle 26.6.9-1
    fixed: vendor fix RHSA-2026:96039
  • Red Hat build of Keycloak 26.6.9
    fixed: vendor fix RHSA-2026:96040
  • Red Hat Single Sign-On 7 keycloak-services 18.0.20.redhat-00001
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
total
Assessed
4d ago

Exploit prediction

0.28% chance of exploitation in the next 30 days, higher than 20% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected products

  • Red Hat Red Hat build of Keycloak 26.6
  • Red Hat Red Hat build of Keycloak 26.6.9
  • Red Hat Red Hat Single Sign-On 7

Classification

Weakness
  • CWE-347 Improper Verification of Cryptographic Signature

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.