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Medium4.7Red Hat Linux

Medium [CVE-2024-9666] Org.keycloak/keycloak-quarkus-server: keycloak proxy header handling denial-of-service (dos) vulnerability

This medium-severity Red Hat Linux advisory covers CVE-2024-9666 affecting Red Hat build of Keycloak 24, Red Hat build of Keycloak 26.0.

CVE-2024-9666 Published Nov 25, 2024Updated by vendor Aug 4, 2026
Affected products & platforms
Red Hat LinuxUnclassified
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Summary

A vulnerability was found in the Keycloak Server. The Keycloak Server is vulnerable to a denial of service (DoS) attack due to improper handling of proxy headers.

When Keycloak is configured to accept incoming proxy headers, it may accept non-IP values, such as obfuscated identifiers, without proper validation. This issue can lead to costly DNS resolution operations, which an attacker could exploit to tie up IO threads and potentially cause a denial of service.

The attacker must have access to send requests to a Keycloak instance that is configured to accept proxy headers, specifically when reverse proxies do not overwrite incoming headers, and Keycloak is configured to trust these headers.

Affected products named by the advisory: Red Hat build of Keycloak 24; Red Hat build of Keycloak 26.0.

Affected versions
  • before 24.0.9
  • 25.0.0 before 26.0.6

Official advisory · high-confidence parse· fetched 2 hours ago·verify at source

Fixed versions
  • 24.0.9
  • 26.0.6

Official advisory · high-confidence parse· fetched 2 hours ago·verify at source

Mitigation

Upgrade to a fixed release: 24.0.9, 26.0.6. That is the remediation for this advisory.

The vendor advisory may list additional interim mitigations or workarounds not captured here — review it before change work.

Official advisory · high-confidence parse· fetched 2 hours ago·verify at source

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