Keycloak Vulnerable to Improper Validation of Specified Quantity in Input
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 silently dropped, causing the system to fall back to client credentials. This allows the user to gain the permissions of the client's service account, leading to privilege escalation.
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beschreibt (1)
Zugehörige CVEs.
| ID | Schweregrad | ausnutzbar | ||
|---|---|---|---|---|
| CVE-2026-9704US | high8.8 | — | ||
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 TokenEndpoi… | ||||
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Referenzen
Externe Belege — Patches, Meldungen, Analysen.
- https://access.redhat.com/errata/RHSA-2026:25097WEB
- https://access.redhat.com/errata/RHSA-2026:25098WEB
- https://access.redhat.com/errata/RHSA-2026:30049WEB
- https://access.redhat.com/errata/RHSA-2026:30050WEB
- https://access.redhat.com/security/cve/CVE-2026-9704WEB
- https://bugzilla.redhat.com/show_bug.cgi?id=2481877WEB
- https://github.com/keycloak/keycloakPACKAGE
- https://github.com/keycloak/keycloak/commit/f1e5b7776c42938d0782fd5846346b8f75c815e6WEB
scry
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