Executive brief
Nuclei is a security scanner that executes JavaScript templates to test web applications and infrastructure. A memory safety vulnerability in its embedded JavaScript engine allows attackers to craft malicious templates that execute arbitrary native code on the scanner host, potentially compromising the entire system. This affects users running untrusted templates from third-party sources or plugin platforms.
Technical details
The vulnerability is an out-of-bounds heap write in the Goja JavaScript runtime (pkg/js/) that Nuclei uses to execute `javascript:` protocol templates. Attackers can craft JavaScript code within templates that corrupts heap memory to achieve native code execution. No authentication or special flags are required—unsigned `javascript:` templates execute by default, and the vulnerability can be triggered through template initialization (`init` section) before other security checks complete. The attack vector is network-accessible if templates come from remote sources. Nuclei v3.10.0 patches the issue by updating the Goja dependency; v3.11.0 adds cryptographic signing requirements for JavaScript templates as additional defense in depth.
Affected products
- ProjectDiscovery Nuclei before 3.10.0
Timeline
- 2026-09-22: disclosed: Published via GitHub Security Advisory GHSA-vxg7-f2jj-jmqm
- 2026-09-22: patched: Fixed in Nuclei v3.10.0 by updating Goja dependency (PR #7467)
- 2026-09-22: other: Additional hardening in v3.11.0 with JavaScript template signing requirement (PR #7514)