Information Disclosure in github.com/projectdiscovery/nuclei/v3 (CVE-2026-76805)
Summary
Vulnerability in github.com/projectdiscovery/nuclei/v3 (CVE-2026-76805). Confidential information can be exposed externally. Exploitable via EnvironmentVariables. Mitigation: upgrade to 3.10.0 or later.
Original description
The description as published by the source.
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 content captured by an internal: true extractor in a prior protocol step could flow into a fuzz payload and be reinterpreted as DSL/helper syntax on a subsequent pass.
When -env-vars (-ev) is enabled, environment variables are merged into the template variable map. A malicious target can return response data containing expressions like {{env_var_name}} which, when reused in a subsequent f…
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-76805 has been found in github.com/projectdiscovery/nuclei/v3.
Attackers can target a specific entry point like EnvironmentVariables over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 5.3/10.
What to do: upgrade github.com/projectdiscovery/nuclei/v3 to 3.10.0 or later.
If unsure, ask your IT team or search "github.com/projectdiscovery/nuclei/v3 CVE-2026-76805" on the vendor's site.
CVE-2026-76805 (github.com/projectdiscovery/nuclei/v3) — CWE-200 / CVSS v3 5.3
Attack vector: remote (network-reachable) / unauthenticated
Attack surface: EnvironmentVariables / true
Patched: 3.10.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Information disclosure (CWE-200) exists in github.com/projectdiscovery/nuclei/v3. Attackers reach the vulnerable code path via EnvironmentVariables without authentication.
Check the vendor advisory for the affected versions of github.com/projectdiscovery/nuclei/v3. Attack surface: EnvironmentVariables / true.
Severity: Medium (CVSS 5.3/10). Confidential information can be exposed externally.
Update to 3.10.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'github.com/projectdiscovery/nuclei/v3' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
grep -r 'github.com/projectdiscovery/nuclei/v3' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
github.com/projectdiscovery/nuclei/v3を grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade github.com/projectdiscovery/nuclei/v3 to 3.10.0ステージング環境で 3.10.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
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3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web github.com
- web github.com
- web github.com