File Path Validation Vulnerability in Keycloak's X.509 Client Certificate Authenticator
CVE-2026-103884

6.5MEDIUM

Key Information:

Vendor

Red Hat
Status
Red Hat Build Of Keycloak
Red Hat Single Sign-on 7
Vendor
CVE Published:
1 October 2026

What is CVE-2026-103884?

A security flaw exists in the X.509 client certificate authenticator of Keycloak, specifically when checking the CRL Distribution Point. The vulnerability occurs due to improper validation of file paths in client certificates. An attacker can exploit this by submitting a carefully crafted certificate, prompting the server to read sensitive files from the local system. This can lead to information disclosure or could exhaust server memory by attempting to load excessively large files, which potentially results in server crashes.

References

https://access.redhat.com/security/cve/CVE-2026-103884
vdb-entryx_refsource_REDHAT

CVSS V3.1

Score:
6.5
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
None
Availability:
Low
Attack Vector:
Network
Attack Complexity:
High
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Red Hat would like to thank Robin Marchand for reporting this issue.
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