CVE-2024-43405

A vulnerability has been identified in Nuclei's template signature verification system that could allow an attacker to bypass the signature check and possibly execute malicious code via custom code template.

Affected Component

The vulnerability is present in the template signature verification process, specifically in the signer package.

Description

The vulnerability stems from a discrepancy between how the signature verification process and the YAML parser handle newline characters, combined with the way multiple signatures are processed. This allows an attacker to inject malicious content into a template while maintaining a valid signature for the benign part of the template.

Affected Users

1. CLI Users: Those executing custom code templates from unverified sources. This includes templates authored by third parties or obtained from unverified repositories.
2. SDK Users: Developers integrating Nuclei into their platforms, particularly if they permit the execution of custom code templates by end-users.

[!NOTE]
Code templates are disabled as default, users have to explicitly enable with -code option.

Proof of Concept

id: example-template
info:
  name: Example Template
# Other benign content...
# digest: <valid_signature_for_benign_content>
# digest: <another_signature>\r
code:\r
  - engine:\r
      - sh\r
      - bash\r
    source: |\r
      id\r

Mitigation

• Immediate Upgrade: The primary recommendation is to upgrade to Nuclei v3.2.0, where the vulnerability has been patched.
• Avoid Unverified Templates: As an interim measure, users should refrain from using custom templates if unable to upgrade immediately. Only trusted, verified templates should be executed.

Workarounds

If you are unable to upgrade nuclei, disable running custom code templates as workaround.

Acknowledgments

We would like to thank Guy Goldenberg from Wiz who reported this to us via our security email, [email protected].

Untrusted input reaches a shell command, allowing arbitrary commands to run on the host. Typical impact: code execution in the application's environment.

CVE-2024-43405 has a CVSS score of 7.4 (Medium). The vector is requires local access, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (3.3.2); upgrading removes the vulnerable code path.

Kodem intelligence

1. The vulnerability is addressed in Nuclei v3.3.2 Users are strongly recommended to update to this version to mitigate the security risk.
2. Fix reference - https://github.com/projectdiscovery/nuclei/commit/0da993afe6d41b4b1b814e8fad23a2acba13c60a

1. What is CVE-2024-43405? CVE-2024-43405 is a medium-severity OS command injection vulnerability in github.com/projectdiscovery/nuclei/v3 (go), affecting versions >= 3.0.0, < 3.3.2. It is fixed in 3.3.2. Untrusted input reaches a shell command, allowing arbitrary commands to run on the host.
2. How severe is CVE-2024-43405? CVE-2024-43405 has a CVSS score of 7.4 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of github.com/projectdiscovery/nuclei/v3 are affected by CVE-2024-43405? github.com/projectdiscovery/nuclei/v3 (go) versions >= 3.0.0, < 3.3.2 is affected.
4. Is there a fix for CVE-2024-43405? Yes. CVE-2024-43405 is fixed in 3.3.2. Upgrade to this version or later.
5. Is CVE-2024-43405 exploitable, and should I be worried? Whether CVE-2024-43405 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2024-43405 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2024-43405? Upgrade github.com/projectdiscovery/nuclei/v3 to 3.3.2 or later.