CVE-2026-9704Network attack vector

Authenticated privilege escalation via silent token removal

Published May 27, 2026 · Updated May 27, 2026

Improper input validation in Red Hat build of Keycloak 26.4 and 26.6 allows remote authenticated users to gain service-account privileges. The OIDC TokenEndpoint silently removes a subject_token JWT longer than 4,000 characters, then token exchange falls back to client credentials. A low-privileged account, an enabled token-exchange flow, and usable client credentials are required; successful requests inherit the client's service-account permissions.

CVSS severity6.8
Medium
EPSS probability0.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Red Hat build of Keycloak 26.4 and 26.6 allows remote authenticated users to gain service-account privileges. The OIDC TokenEndpoint silently removes a subject_token JWT longer than 4,000 characters, then token exchange falls back to client credentials. A low-privileged account, an enabled token-exchange flow, and usable client credentials are required; successful requests inherit the client's service-account permissions.

The record

CVE
CVE-2026-9704
Published
May 27, 2026
Updated
May 27, 2026
Vendor
389 Directory Server
Product
Red Hat build of Keycloak
Classifications
CWE-1284, T1068
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 27, 2026CVE publishedPublication date reported by the CVE source.
  2. May 27, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

389 Directory Server · Red Hat build of KeycloakAffected versions are unavailable in this record.

Published CVSS scores

6.8Red Hat, Inc.CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1284Improper Validation of Specified Quantity in Input
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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