CVE-2026-15571 (GCVE-0-2026-15571)

Vulnerability from cvelistv5 – Published: 2026-08-18 20:40 – Updated: 2026-08-19 01:55
VLAI
Title
Keycloak-services: keycloak-services: predictable account-linking hash enables account takeover via malicious oidc client
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.
Severity
7.3 (High)
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N
CWE
  • CWE-341 - Predictable from Observable State
Assigner
References
URL Tags
https://access.redhat.com/errata/RHSA-2026:56523 vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:56524 vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/security/cve/CVE-2026-15571 vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2499591 issue-trackingx_refsource_REDHAT
Impacted products
Vendor Product Version CPE status
Red Hat Red Hat build of Keycloak 26.6 Unaffected: 26.6.6-1 , < * (rpm)
    cpe:/a:redhat:build_keycloak:26.6::el9
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Red Hat Red Hat build of Keycloak 26.6 Unaffected: 26.6-12 , < * (rpm)
    cpe:/a:redhat:build_keycloak:26.6::el9
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Red Hat Red Hat build of Keycloak 26.6.6     cpe:/a:redhat:build_keycloak:26.6
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Red Hat Red Hat Data Grid 8     cpe:/a:redhat:jboss_data_grid:8
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Red Hat Red Hat JBoss Enterprise Application Platform Expansion Pack     cpe:/a:redhat:jbosseapxp
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Red Hat Red Hat Single Sign-On 7     cpe:/a:redhat:red_hat_single_sign_on:7
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Date Public
2026-08-18 19:41
Credits
Red Hat would like to thank yd1ng for reporting this issue.
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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.