---
id: "CVE-2026-76805"
kind: "vulnerability"
aliases: ["CVE-2026-76805", "GHSA-jpvm-9frm-hjcq", "GO-2026-6571"]
title: "Nuclei: Environment Variable Disclosure via Response-Derived Data in DAST/Fuzz Mode in github.com/projectdiscovery/nuclei"
severity: "medium"
cvss: 5.3
epss: 0.0041
exploited: false
status: "open"
category: "package"
products: [{"name": "github.com/projectdiscovery/nuclei", "fixed": [], "affected": "all versions", "ecosystem": "go"}, {"name": "github.com/projectdiscovery/nuclei/v2", "fixed": [], "affected": "all versions", "ecosystem": "go"}, {"name": "github.com/projectdiscovery/nuclei/v3", "fixed": ["3.10.0"], "affected": ">= 3.0.0, < 3.10.0", "ecosystem": "go"}]
ecosystems: ["go"]
tags: ["ci", "go", "nuclei", "package", "scanner-operators"]
not_affected_if: ["default-config", "no-env-vars-flag", "single-step-templates", "version-3.10.0-or-later"]
published_at: "2026-09-22T17:17:25+00:00"
first_seen_at: "2026-10-23T19:13:08+00:00"
updated_at: "2026-10-23T21:48:57+00:00"
sources: [{"source": "govuln", "url": "https://pkg.go.dev/vuln/GO-2026-6571", "first_seen_at": "2026-10-23T19:13:08+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-76805", "first_seen_at": "2026-10-23T19:13:43+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-76805", "first_seen_at": "2026-10-23T19:35:23+00:00"}]
---

# Nuclei: Environment Variable Disclosure via Response-Derived Data in DAST/Fuzz Mode in github.com/projectdiscovery/nuclei

Nuclei's DAST/fuzz path can evaluate response data a second time as template syntax, so a malicious scan target can make the scanner resolve host environment variables. An attacker who controls a scan target can read scanner-host secrets such as credentials, API keys, or tokens.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- go:github.com/projectdiscovery/nuclei affected all versions fixed ?
- go:github.com/projectdiscovery/nuclei/v2 affected all versions fixed ?
- go:github.com/projectdiscovery/nuclei/v3 affected >= 3.0.0, < 3.10.0 fixed 3.10.0

## How to check

Check the go.mod of each project that uses Nuclei for github.com/projectdiscovery/nuclei/v3 below 3.10.0.
Search scan scripts and CI configs for the -env-vars flag combined with multi-step DAST or fuzz templates.

## Fix

Upgrade github.com/projectdiscovery/nuclei/v3 to 3.10.0 or later.
Until upgraded, do not run -env-vars against untrusted targets.

## Timeline

- 2026-10-23T19:13:08+00:00 govuln https://pkg.go.dev/vuln/GO-2026-6571
- 2026-10-23T19:13:43+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-76805
- 2026-10-23T19:35:23+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-76805

## From the sources

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.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_