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Fencer Intel
high 7.3

CVE-2026-3872 json

Keycloak: keycloak: information disclosure due to redirect_uri validation bypass

published 7mo ago modified 14d ago also BIT-keycloak-2026-3872 , EUVD-2026-18206 , GHSA-cjm2-j6cm-6p6m

cvss
7.3
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 39%
public exploits
0
none known

Summary

A flaw was found in Keycloak. This issue allows an attacker, who controls another path on the same web server, to bypass the allowed path in redirect Uniform Resource Identifiers (URIs) that use a wildcard. A successful attack may lead to the theft of an access token, resulting in information disclosure.

Patch / fix

  • maven org.keycloak:keycloak-services 26.5.7
  • bitnami keycloak 26.2.1, 26.3.0, 26.4.1, 26.5.0
  • Red Hat Red Hat build of Keycloak 26.2 26.2-18, 26.2.15-1
  • Red Hat Red Hat build of Keycloak 26.4 26.4-14, 26.4.11-1

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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-2026-3872 updated cvss 7.3

keycloak: Keycloak: Information disclosure due to redirect_uri validation bypass

  • Red Hat build of Keycloak 26.2 rhbk/keycloak-rhel9 26.2-18, rhbk/keycloak-rhel9-operator 26.2-18, rhbk/keycloak-operator-bundle 26.2.15-1
    fixed: vendor fix RHSA-2026:6476
  • Red Hat build of Keycloak 26.2.15
    fixed: vendor fix RHSA-2026:6475
  • Red Hat build of Keycloak 26.4 rhbk/keycloak-rhel9 26.4-14, rhbk/keycloak-rhel9-operator 26.4-14, rhbk/keycloak-operator-bundle 26.4.11-1
    fixed: vendor fix RHSA-2026:6478
  • Red Hat build of Keycloak 26.4.11
    fixed: vendor fix RHSA-2026:6477

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
total
Assessed
7mo ago

Exploit prediction

0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 7.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N
CISA ADP 3.1 7.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N
GitHub 3.1 7.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N
OSV 3.1 7.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N

Affected packages

ecosystem package affected fixed in
maven org.keycloak:keycloak-services
<26.5.7
26.5.7
bitnami keycloak
>=26.2.0, <26.2.1
>=26.2.15, <26.3.0
>=26.4.0, <26.4.1
>=26.4.11, <26.5.0
26.2.1
26.3.0
26.4.1
26.5.0

Affected products

  • Red Hat Red Hat build of Keycloak 26.2
  • Red Hat Red Hat build of Keycloak 26.2.15
  • Red Hat Red Hat build of Keycloak 26.4
  • Red Hat Red Hat build of Keycloak 26.4.11

Classification

Weakness
  • CWE-601 URL Redirection to Untrusted Site

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.