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

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.3 · CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N

EPSS

• CVE-2026-76805: 0.41% estimated exploitation activity in the next 30 days; percentile 35.34 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

A vulnerability in Nuclei's DAST/fuzz expression evaluation path allows a malicious target server to trigger disclosure of scanner-host environment variables when the -env-vars / -ev option is explicitly enabled. This is an incomplete fix for CVE-2026-41645 / GHSA-jm34-66cf-qpvr. The original fix hardened expressions.Evaluate() to be single-pass within one call, but did not address callers that invoked evaluation multiple times on substituted output in the DAST/fuzz pipeline. Affected Component The issue is in the DAST/fuzz payload evaluation path (pkg/fuzz/parts.go) and the shared template rendering boundary. When a multi-step template captures response data via an internal extractor and reuses it in a subsequent fuzz step, the fuzz evaluator could treat the substituted response content as fresh template syntax on a second evaluation pass. Description In DAST/fuzz mode, payload evaluation previously ran expression substitution more than once on the same value. Response-derived…

Published by the source

22 Sep 2026, 20:37 UTC

Last modified by the source

1 Oct 2026, 20:45 UTC

Source last checked

26 Oct 2026, 15:29 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-jpvm-9frm-hjcq

2. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GO-2026-6571

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-jpvm-9frm-hjcq

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# Patch Next advisory brief: CVE-2026-76805

Advisory: Nuclei: Environment Variable Disclosure via Response-Derived Data in DAST/Fuzz Mode
IDs: CVE-2026-76805, GHSA-jpvm-9frm-hjcq
Record: https://patchnext.com/advisories/cve-2026-76805 (revision 3, source checked 26 Oct 2026, 15:29 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Partial vendor fix; fixed versions by package: github.com/projectdiscovery/nuclei/v3 3.10.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/projectdiscovery/nuclei: affected every version
- Go github.com/projectdiscovery/nuclei/v3: affected >= 3.0.0, < 3.10.0; fixed in 3.10.0
- Go github.com/projectdiscovery/nuclei/v2: affected every version

## Suggested inspection (read-only)
- Go github.com/projectdiscovery/nuclei: check the installed version with your package manager.
- Go github.com/projectdiscovery/nuclei/v3: check the installed version with your package manager.
- Go github.com/projectdiscovery/nuclei/v2: check the installed version with your package manager.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/projectdiscovery/nuclei, github.com/projectdiscovery/nuclei/v3, github.com/projectdiscovery/nuclei/v2.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-jpvm-9frm-hjcq (OSV record GHSA-jpvm-9frm-hjcq lists affected ranges: Go github.com/projectdiscovery/nuclei/v3 >=3.0.0 <3.10.0 (fixed))
- Verified: https://osv.dev/vulnerability/GO-2026-6571 (OSV record GO-2026-6571 lists affected ranges: Go github.com/projectdiscovery/nuclei >=0; Go github.com/projectdiscovery/nuclei/v2 >=0; Go github.com/projectdiscovery/nuclei/v3 >=3.0.0 <3.10.0 (fixed))
- Verified: https://github.com/advisories/GHSA-jpvm-9frm-hjcq (GitHub-reviewed advisory GHSA-jpvm-9frm-hjcq lists affected ranges: Go github.com/projectdiscovery/nuclei/v3 >=3.0.0 <3.10.0)

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