Nuclei: Environment Variable Disclosure via Response-Derived Data in DAST/Fuzz Mode (CVE-2026-76805) | HOL Guard CVE

Medium · CVSS 5.3CVE-2026-76805

Nuclei: Environment Variable Disclosure via Response-Derived Data in DAST/Fuzz Mode

Answer in brief

CVE-2026-76805 records a Medium severity (CVSS 5.3) vulnerability in Nuclei: Environment Variable Disclosure via Response-Derived Data in DAST/Fuzz Mode. The current sources do not mark it as known exploited. The current feed maps projectdiscovery/nuclei (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 22, 2026Updated Sep 22, 2026Source checked Sep 22, 2026First seen by HOL Sep 22, 2026Material review Sep 22, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 5.3
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Not reported

Why this deserves its current priority

CVSS is 5.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps projectdiscovery/nuclei (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
projectdiscovery/nucleigeneric	>= 3.0.0, < 3.10.0	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for projectdiscovery/nuclei.
Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

Published upstream
Sep 22, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 22, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 22, 2026

Sources and claim methodology

Upstream source description

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.

Quoted source text, attributed separately from HOL analysis.