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Nuclei: Arbitrary Code Execution via Goja JavaScript Engine Vulnerability
High severity
GitHub Reviewed
Published
Jul 16, 2026
in
projectdiscovery/nuclei
•
Updated Sep 22, 2026
A vulnerability in the Goja JavaScript engine used by Nuclei's javascript: protocol allows arbitrary native code execution on the scanner host when running untrusted JavaScript templates.
Affected Component
The issue is in the Goja JavaScript runtime embedded in Nuclei's JavaScript protocol (pkg/js/). An out-of-bounds heap write in the engine can be exploited to achieve native code execution during template evaluation.
Description
Nuclei uses the Goja engine to execute javascript: protocol templates. A memory safety vulnerability in Goja allows attacker-controlled JavaScript to corrupt heap memory and execute arbitrary native code on the host running Nuclei.
Because javascript: templates execute without the -code flag and unsigned JavaScript templates run by default, a malicious template from an untrusted source can trigger code execution during a normal scan. The vulnerability could also be reached through a template's init section, which runs during template initialization before other security checks complete.
Note
JavaScript templates do not require the -code flag and are not subject to the code-template signing requirement on affected versions. Nuclei v3.11.0 adds a separate signing requirement for JavaScript templates as additional defense in depth.
Affected Users
CLI users running untrusted or third-party javascript: templates.
SDK users who integrate Nuclei into platforms where end users can supply JavaScript templates.
Patches
The vulnerability is fixed in Nuclei v3.10.0 by updating the Goja dependency. Upgrading is strongly recommended.
Additional hardening in v3.11.0 requires cryptographic signatures for JavaScript templates: projectdiscovery/nuclei#7514
Mitigation
Upgrade to Nuclei v3.10.0 or later. For additional protection, upgrade to v3.11.0 where JavaScript templates also require valid signatures.
In the meantime, avoid running JavaScript templates from unverified sources.
Workarounds
If upgrading is not an option, do not run untrusted JavaScript templates. There is no configuration flag that mitigates native code execution on affected versions.
Acknowledgments
Thanks to Dylan Pindur (@dpindur) and Adam Kues (@akues-an) of the Assetnote security research team for reporting this issue through responsible disclosure via security@projectdiscovery.io.
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akues-an Reporter
A vulnerability in the Goja JavaScript engine used by Nuclei's
javascript:protocol allows arbitrary native code execution on the scanner host when running untrusted JavaScript templates.Affected Component
The issue is in the Goja JavaScript runtime embedded in Nuclei's JavaScript protocol (
pkg/js/). An out-of-bounds heap write in the engine can be exploited to achieve native code execution during template evaluation.Description
Nuclei uses the Goja engine to execute
javascript:protocol templates. A memory safety vulnerability in Goja allows attacker-controlled JavaScript to corrupt heap memory and execute arbitrary native code on the host running Nuclei.Because
javascript:templates execute without the-codeflag and unsigned JavaScript templates run by default, a malicious template from an untrusted source can trigger code execution during a normal scan. The vulnerability could also be reached through a template'sinitsection, which runs during template initialization before other security checks complete.Note
JavaScript templates do not require the
-codeflag and are not subject to the code-template signing requirement on affected versions. Nuclei v3.11.0 adds a separate signing requirement for JavaScript templates as additional defense in depth.Affected Users
javascript:templates.Patches
Mitigation
Upgrade to Nuclei v3.10.0 or later. For additional protection, upgrade to v3.11.0 where JavaScript templates also require valid signatures.
In the meantime, avoid running JavaScript templates from unverified sources.
Workarounds
If upgrading is not an option, do not run untrusted JavaScript templates. There is no configuration flag that mitigates native code execution on affected versions.
Acknowledgments
Thanks to Dylan Pindur (@dpindur) and Adam Kues (@akues-an) of the Assetnote security research team for reporting this issue through responsible disclosure via security@projectdiscovery.io.
References