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CVE-2024-9666

MEDIUM

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…

Published
Nov 25, 2024
Updated
Jun 17, 2026
Affected
0 pkgs
Patched
None yet
Exploits
None indexed

EPSS Exploitation Probability

via FIRST.org ↗
0.4%probability of exploitation in next 30 days
Lower Risk31th percentile+0.38%
0.00%0.30%0.60%0.90%0.0%0.4%Dec 25Apr 26Jun 26

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Description

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.

Detection & mitigation playbook

Vulnerability
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

  2. Remediation status

    No patched version of the affected component has shipped for CVE-2024-9666 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.

  3. Mitigate without a patch

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 pinpoints whether CVE-2024-9666 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2024-9666. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

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 re
O3 Security · Impact-Aware SCA

Is CVE-2024-9666 in your dependencies?

O3 detects CVE-2024-9666 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

CVE-2024-9666: CWE-444 (Medium 4.7) | O3 Security