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Security Advisories: GSA_kwCzR0hTQS1qZ3djLWpoODktcnBncc4ABBve

Keycloak proxy header handling Denial-of-Service (DoS) vulnerability

Keycloak versions 26 and earlier are vulnerable to a denial-of-service (DoS) attack through 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 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.

For Keycloak version 26, for successful exploitation includes: the realm must have SslRequired=EXTERNAL (the default), HTTP must be enabled, the instance must not be using a full hostname URL, access must come from behind a proxy (assuming the proxy overwrites the X-Forwarded-For header), and trusted proxies must not be set or must incorrectly trust the client from which the request is originating.

Permalink: https://github.com/advisories/GHSA-jgwc-jh89-rpgq
JSON: https://advisories.ecosyste.ms/api/v1/advisories/GSA_kwCzR0hTQS1qZ3djLWpoODktcnBncc4ABBve
Source: GitHub Advisory Database
Origin: Unspecified
Severity: Moderate
Classification: General
Published: 16 days ago
Updated: 16 days ago


CVSS Score: 4.7
CVSS vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS Percentage: 0.00044
EPSS Percentile: 0.11709

Identifiers: GHSA-jgwc-jh89-rpgq, CVE-2024-9666
References: Repository: https://github.com/keycloak/keycloak
Blast Radius: 6.6

Affected Packages

maven:org.keycloak:keycloak-quarkus-server
Dependent packages: 5
Dependent repositories: 25
Downloads:
Affected Version Ranges: >= 25.0.0, < 26.0.6, < 24.0.9
Fixed in: 26.0.6,
All affected versions: 12.0.0, 12.0.1, 12.0.2, 12.0.3, 12.0.4, 13.0.0, 13.0.1, 14.0.0, 15.0.0, 15.0.1, 15.0.2, 15.1.0, 15.1.1, 16.0.0, 16.1.0, 16.1.1, 17.0.0, 17.0.1, 18.0.0, 18.0.1, 18.0.2, 19.0.0, 19.0.1, 19.0.2, 19.0.3, 20.0.0, 20.0.1, 20.0.2, 20.0.3, 20.0.4, 20.0.5, 21.0.0, 21.0.1, 21.0.2, 21.1.0, 21.1.1, 21.1.2, 22.0.0, 22.0.1, 22.0.2, 22.0.3, 22.0.4, 22.0.5, 23.0.0, 23.0.1, 23.0.2, 23.0.3, 23.0.4, 23.0.5, 23.0.6, 23.0.7, 24.0.0, 24.0.1, 24.0.2, 24.0.3, 24.0.4, 24.0.5, 25.0.0, 25.0.1, 25.0.2, 25.0.3, 25.0.4, 25.0.5, 25.0.6, 26.0.0, 26.0.1, 26.0.2, 26.0.4, 26.0.5
All unaffected versions: 26.0.6