ProjectDiscovery Nuclei up to 3.9.x DAST/Fuzz Payload Path pkg/fuzz/parts.go expressions.Evaluate information disclosure

Summaryinfo

A vulnerability has been found in ProjectDiscovery Nuclei up to 3.9.x and classified as problematic. This affects the function expressions.Evaluate of the file pkg/fuzz/parts.go of the component DAST/Fuzz Payload Path. Performing a manipulation results in information disclosure. This vulnerability is reported as CVE-2026-76805. The attack is possible to be carried out remotely. No exploit exists. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as problematic has been found in ProjectDiscovery Nuclei up to 3.9.x. This affects the function expressions.Evaluate of the file pkg/fuzz/parts.go of the component DAST/Fuzz Payload Path. The manipulation with an unknown input leads to a information disclosure vulnerability. CWE is classifying the issue as CWE-200. The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. This is going to have an impact on confidentiality. The summary by CVE is:

Nuclei is a vulnerability scanner built on a simple YAML-based DSL. From 3.0.0 until 3.10.0, the DAST/fuzz payload path in pkg/fuzz/parts.go can evaluate substituted runtime data more than once, creating a second evaluation pass that allows response content captured by an internal: true extractor in one protocol step to be reinterpreted as template syntax in a later fuzz step. This vulnerability is an incomplete fix for CVE-2026-41645: the prior remediation made expressions.Evaluate() single-pass within one call but did not prevent DAST/fuzz callers from evaluating substituted output again. When -env-vars is enabled, a malicious scan target can return marker-shaped content that resolves against the template variable map and discloses scanner-host environment variables such as credentials, API keys, or tokens. The vulnerability requires a multi-step DAST or fuzz template, response data reused through an internal extractor, and explicit environment-variable expansion; users who do not enable -env-vars are not affected by the sensitive-information disclosure. This issue is fixed in version 3.10.0.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-76805 since 08/19/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1592 for this issue.

Upgrading to version 3.10.0 eliminates this vulnerability.

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Productinfo

Type

• Project Management Software

Vendor

• ProjectDiscovery

Name

• Nuclei

Version

• 3.0
• 3.1
• 3.2
• 3.3
• 3.4
• 3.5
• 3.6
• 3.7
• 3.8
• 3.9

Website

• Product: https://github.com/projectdiscovery/nuclei/

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