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Fencer Vulns
low 3.7

CVE-2026-4633 json

Keycloak: keycloak: user enumeration via differential error messages

published 2026-03-23 7 mo ago modified 2026-10-23 17 d ago also GHSA-rhgq-f8x5-j2jc , EUVD-2026-14400

cvss
3.7
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 remote attacker can exploit differential error messages during the identity-first login flow when Organizations are enabled. This vulnerability allows an attacker to determine the existence of users, leading to information disclosure through user enumeration.

Patch / fix

  • maven org.keycloak:keycloak-services 26.4.12, 26.6.1

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-2026-4633 updated cvss 3.7

keycloak: Keycloak: User enumeration via differential error messages

  • Red Hat Build of Keycloak rhbk/keycloak-rhel9
    affected: workaround, no fix available
  • 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
7 mo ago

Exploit prediction

0.42% chance of exploitation in the next 30 days, higher than 36% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • bugzilla.redhat.com https://bugzilla.redhat.com/show_bug.cgi?id=2450247 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
NVD 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
GitHub 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

Affected packages

ecosystem package affected fixed in
maven org.keycloak:keycloak-services
>=26.5.0, <26.6.1
<26.4.12
26.6.1
26.4.12

Affected products

  • Red Hat Red Hat build of Keycloak 26.4.12
  • Red Hat Red Hat Build of Keycloak

Classification

Weakness
  • CWE-209 Generation of Error Message Containing Sensitive Information

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.