CVE-2026-16102: Access Control Flaw (CVSS 8.1)

Description

A flaw was found in the Dynamic Client Registration (DCR) component of Keycloak, an identity and access management solution. The default DCR policy fails to properly validate the claim path for User Property mappers, allowing them to write values to sensitive internal claim locations. An attacker with a standard user account and a limited Initial Access Token can exploit this to forge administrative roles in their access token. This allows the attacker to take over other clients, steal confidential secrets, and potentially gain full administrative control over the realm.

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CVSS v3.1 Score

8.1

HIGH

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Weakness Type (CWE)

CWE-284 CWE-284

References

Other References

https://access.redhat.com/errata/RHSA-2026:50846 https://access.redhat.com/errata/RHSA-2026:50847 https://access.redhat.com/errata/RHSA-2026:50848 https://access.redhat.com/errata/RHSA-2026:50849 https://access.redhat.com/security/cve/CVE-2026-16102 https://bugzilla.redhat.com/show_bug.cgi?id=2501735

Frequently Asked Questions

What is CVE-2026-16102? +

A flaw was found in the Dynamic Client Registration (DCR) component of Keycloak, an identity and access management solution. The default DCR policy fails to properly validate the claim path for User Property mappers, allowing them to write values to sensitive internal claim locations. An attacker with a standard user account and a limited Initial Access Token can exploit this to forge administrative roles in their access token. This allows the attacker to take over other clients, steal confidential secrets, and potentially gain full administrative control over the realm. It has a CVSS v3.1 base score of 8.1 (HIGH).

How severe is CVE-2026-16102? +

CVE-2026-16102 has a CVSS v3.1 score of 8.1 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

How do I check if I'm vulnerable to CVE-2026-16102? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2026-16102