Summary
Nuclei: Arbitrary Command Execution via DAST Code Signature Bypass
A vulnerability in Nuclei's DAST template loading path allows unsigned code: protocol templates to execute, bypassing the cryptographic signature requirement that is meant to prevent arbitrary command execution from untrusted templates.
Affected Component
The issue is in the template loader's DAST loading branch. When -dast is enabled and a template contains a fuzzing: block, the loader accepted the template through a code path that omitted the unsigned-code-template signature check present in the normal loading branch.
Description
Nuclei requires code: protocol templates to be cryptographically signed before execution. Unsigned code templates are normally skipped with a warning. However, when a template combined a fuzzing: block (making it DAST-eligible) with an unsigned code: block, enabling -dast routed the template through the DAST loader branch, which did not enforce signature verification.
For multiprotocol templates containing both HTTP and code: blocks, the unsigned code request was included in the execution queue regardless of whether -code was set. This allowed arbitrary shell command execution from an unsigned code: block with only -dast enabled.
[!NOTE]
Both DAST mode (-dast) and code-protocol templates are disabled by default. Code templates normally require both the -code flag and a valid template signature. This issue bypassed the signature and -code controls only when -dast was explicitly enabled.
Affected Users
- CLI users running DAST/fuzzing scans (
-dast) with untrusted or attacker-supplied templates that contain bothfuzzing:andcode:blocks. - SDK users who integrate Nuclei with DAST mode enabled and allow end users to supply custom templates.
Patches
- The vulnerability is fixed in Nuclei v3.10.0. Upgrading is strongly recommended.
- Fix reference: https://github.com/projectdiscovery/nuclei/pull/7472
Mitigation
Upgrade to Nuclei v3.10.0, where code template signature verification is enforced before DAST loading.
In the meantime, avoid running DAST scans with untrusted templates.
Workarounds
If upgrading is not an option, do not use -dast with templates from unverified sources.
Acknowledgments
Thanks to @daffainfo for reporting this issue.
Impact
Untrusted input reaches a shell command, allowing arbitrary commands to run on the host. Typical impact: code execution in the application's environment.
CVE-2026-76802 has a CVSS score of 4.7 (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 (3.10.0); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
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. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2026-76802? CVE-2026-76802 is a medium-severity OS command injection vulnerability in github.com/projectdiscovery/nuclei/v3 (go), affecting versions >= 3.0.0, < 3.10.0. It is fixed in 3.10.0. Untrusted input reaches a shell command, allowing arbitrary commands to run on the host.
- How severe is CVE-2026-76802? CVE-2026-76802 has a CVSS score of 4.7 (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.
- Which versions of github.com/projectdiscovery/nuclei/v3 are affected by CVE-2026-76802? github.com/projectdiscovery/nuclei/v3 (go) versions >= 3.0.0, < 3.10.0 is affected.
- Is there a fix for CVE-2026-76802? Yes. CVE-2026-76802 is fixed in 3.10.0. Upgrade to this version or later.
- Is CVE-2026-76802 exploitable, and should I be worried? Whether CVE-2026-76802 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
- What actually determines whether CVE-2026-76802 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.
- How do I fix CVE-2026-76802? Upgrade
github.com/projectdiscovery/nuclei/v3to 3.10.0 or later.