What is CVE-2026-9704?

CVE-2026-9704 is a medium-severity vulnerability in Red Hat Build Of Keycloak, classified under Improper Validation of Specified Quantity in Input. CVSS score: 6.8/10. Published 2026-05-27.

How severe is CVE-2026-9704?

Medium severity. CVSS v3 base score is 6.8 out of 10.

Vulnerability in Red Hat Build Of Keycloak

CVE-2026-9704

A flaw was found in Keycloak. An authenticated user with low privileges can exploit this vulnerability by sending an oversized subject_token JSON Web Token (JWT) to the TokenEndpoint. When the token exceeds a 4000-character limit, it is si…

EPSS: 0.000 (14.1th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.8 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N.

Affected products

Weakness classification (CWE)

CWE-1284 — Improper Validation of Specified Quantity in Input

References

secalert@redhat.com (x_refsource_REDHAT, Mitigation, vdb-entry, Vendor Advisory)
secalert@redhat.com (x_refsource_REDHAT, issue-tracking, Issue Tracking, Vendor Advisory)

Frequently asked questions

What is CVE-2026-9704?: CVE-2026-9704 is a medium-severity vulnerability in Red Hat Build Of Keycloak, classified under Improper Validation of Specified Quantity in Input. CVSS score: 6.8/10. Published 2026-05-27.
How severe is CVE-2026-9704?: Medium severity. CVSS v3 base score is 6.8 out of 10.