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Fencer Vulns
high 7.3

CVE-2026-15571 json

Keycloak-services: keycloak-services: predictable account-linking hash enables account takeover via malicious oidc client

published 2026-08-18 2 mo ago modified 2026-08-26 2 mo ago also BIT-keycloak-2026-15571 , EUVD-2026-61238

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 37%
public exploits
0
none known

Summary

A flaw was found in the legacy client-initiated account-linking endpoint of Keycloak, a widely used open-source identity and access management solution. The mechanism used to protect the account-linking process from unauthorized requests relies on a hash that can be predicted by a malicious OIDC client. By tricking a user into authenticating, an attacker-controlled client can forge a valid linking URL to connect the victim's account to an attacker's external identity. This results in a full account takeover, allowing the attacker to log in as the victim.

Patch / fix

  • bitnami keycloak 26.7.2
  • Red Hat Red Hat build of Keycloak 26.6 26.6-12, 26.6.6-1

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-2026-15571 updated cvss 7.3

keycloak-services: keycloak-services: Predictable account-linking hash enables account takeover via malicious OIDC client

  • Red Hat build of Keycloak 26.6 rhbk/keycloak-rhel9 26.6-12, rhbk/keycloak-rhel9-operator 26.6-12, rhbk/keycloak-operator-bundle 26.6.6-1
    fixed: vendor fix RHSA-2026:56524
  • Red Hat build of Keycloak 26.6.6
    fixed: vendor fix RHSA-2026:56523
  • Red Hat Data Grid 8 keycloak-services 23.0.7 Red Hat JBoss Enterprise Application Platform Expansion Pack keycloak-services 23.0.7
    not affected: component not present
  • Red Hat Single Sign-On 7 keycloak-services 23.0.7
    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
no
Technical impact
total
Assessed
2 mo ago

Exploit prediction

0.43% chance of exploitation in the next 30 days, higher than 37% of all scored CVEs (FIRST EPSS, 2026-11-08).

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
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
bitnami keycloak
<26.7.2
26.7.2

Affected products

  • Red Hat Red Hat build of Keycloak 26.6
  • Red Hat Red Hat build of Keycloak 26.6.6
  • Red Hat Red Hat Data Grid 8
  • Red Hat Red Hat JBoss Enterprise Application Platform Expansion Pack
  • Red Hat Red Hat Single Sign-On 7

Classification

Weakness
  • CWE-341 Predictable from Observable State

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.