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Fencer Vulns
high 7.1

CVE-2026-7571 json

Keycloak: keycloak: access token disclosure and implicit flow bypass via forged client data

published 2026-05-19 5 mo ago modified 2026-10-26 13 d ago also BIT-keycloak-2026-7571 , EUVD-2026-30888 , GHSA-hq3p-w4xv-x7vp

cvss
7.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 36%
public exploits
0
none known

Summary

A flaw was found in Keycloak. A low-privilege user, with knowledge of user credentials and client ID, can bypass a security control intended to disable the implicit flow in OpenID Connect (OIDC) clients. By manipulating client data during a session restart, an attacker can obtain an access token that should not be available. This vulnerability can also lead to the exposure of these access tokens in server logs, proxy logs, and HTTP Referrer headers, resulting in sensitive information disclosure.

Patch / fix

  • maven org.keycloak:keycloak-services 26.6.2
  • bitnami keycloak 26.4.12
  • Red Hat Red Hat build of Keycloak 26.4 26.4-17, 26.4.12-1

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-2026-7571 updated cvss 7.1

keycloak: Keycloak: Access token disclosure and implicit flow bypass via forged client data

  • Red Hat build of Keycloak 26.4 rhbk/keycloak-rhel9 26.4-17, rhbk/keycloak-rhel9-operator 26.4-17, rhbk/keycloak-operator-bundle 26.4.12-1
    fixed: vendor fix RHSA-2026:19597
  • Red Hat build of Keycloak 26.4.12
    fixed: vendor fix RHSA-2026:19596

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
no
Technical impact
partial
Assessed
5 mo ago

Exploit prediction

0.41% chance of exploitation in the next 30 days, higher than 36% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N
GitHub 3.1 7.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N
OSV 3.1 7.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N

Affected packages

ecosystem package affected fixed in
maven org.keycloak:keycloak-services
<26.6.2
26.6.2
bitnami keycloak
>=26.4.0, <26.4.12
26.4.12

Affected products

  • Red Hat Red Hat build of Keycloak 26.4
  • Red Hat Red Hat build of Keycloak 26.4.12

Classification

Weakness
  • CWE-472 External Control of Assumed-Immutable Web Parameter

References

Sources

Fencer Vulns 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.