CVE-2024-9666
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.
Scoring
- Severity
- MEDIUM
- CVSS base 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 probability
- 0.40%
- CWE
- CWE-444
- Published
- 2024-11-25
- Last modified
- 2026-08-31
Affected products
- Red Hat Red Hat build of Keycloak 24
- Red Hat Red Hat build of Keycloak 24
- Red Hat Red Hat build of Keycloak 26.0
- Red Hat Red Hat build of Keycloak 26.0
- Red Hat Red Hat build of Keycloak 26.0
Weakness type
Related vulnerabilities
- CVE-2023-46589 — Apache Tomcat: HTTP request smuggling via malformed trailer headers
- CVE-2026-48710 — Starlette has missing Host header validation that poisons request.url.path, bypassing path-based security checks
- CVE-2023-33193 — Emby Server Proxy Header Spoofing Vulnerability
- CVE-2025-1867 — HTTP Response Smuggling Vulnerability in libhv
- CVE-2024-41110 — Moby authz zero length regression
- CVE-2023-46846 — Squid: request/response smuggling in http/1.1 and icap
- CVE-2024-27922 — HTTP Handling Vulnerability in the Bare server
- CVE-2026-28497 — TinyWeb: Integer Overflow in `_Val` (HTTP Request Smuggling)