CVE-2026-9704 (GCVE-0-2026-9704)
Vulnerability from cvelistv5
Published
2026-05-27 12:56
Modified
2026-06-10 21:21
Severity ?
VLAI Severity ?
EPSS score ?
CWE
- CWE-1284 - Improper Validation of Specified Quantity in Input
Summary
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.
References
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Impacted products
| Vendor | Product | Version | |||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Red Hat | Red Hat build of Keycloak 26.6 |
Unaffected: 26.6.3-3 < * cpe:/a:redhat:build_keycloak:26.6::el9 |
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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