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Nuclei: Arbitrary Command Execution via DAST Code Signature Bypass

Moderate severity GitHub Reviewed Published Jul 16, 2026 in projectdiscovery/nuclei • Updated Sep 22, 2026

Package

gomod github.com/projectdiscovery/nuclei/v3 (Go)

Affected versions

>= 3.0.0, < 3.10.0

Patched versions

3.10.0

Description

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 both fuzzing: and code: blocks.
  • SDK users who integrate Nuclei with DAST mode enabled and allow end users to supply custom templates.

Patches

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.

References

@ehsandeep ehsandeep published to projectdiscovery/nuclei Jul 16, 2026
Published by the National Vulnerability Database Sep 22, 2026
Published to the GitHub Advisory Database Sep 22, 2026
Reviewed Sep 22, 2026
Last updated Sep 22, 2026

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Local
Attack complexity
High
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(7th percentile)

Weaknesses

Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component. Learn more on MITRE.

CVE ID

CVE-2026-76802

GHSA ID

GHSA-jpf4-98qj-qr67

Source code

Credits

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