Nuclei: Local File Read via Workflow File-Protocol Gate Bypass

A vulnerability in Nuclei's workflow template loader allows file: protocol templates to execute without the -file flag, bypassing a security gate that is meant to prevent local file reads on the scanner host.

Affected Component

The issue is in the workflow template loading path. The main template loader enforces the -file gate for file-protocol templates, but the workflow loader did not apply the same check when resolving templates referenced by a workflow.

Description

Nuclei disables file-protocol templates by default because they read local files from the host running the scanner. Operators must explicitly enable them with the -file flag. When a workflow references a file-protocol template, the workflow loader accepted and executed that template without verifying that -file was enabled.

Because workflows run unsigned by default, an untrusted workflow could load and execute a file-protocol template and read local files from the scan target path, even though the operator had not enabled file templates.

[!NOTE]
File-protocol templates are disabled by default. This issue only affects users who run workflows from untrusted sources without having explicitly enabled -file.

Affected Users

• CLI users running workflows (-w) that reference file-protocol templates from untrusted or third-party sources.
• SDK users who integrate Nuclei into platforms where end users can supply workflow files and rely on the default -file restriction to block local file access.

Patches

• The vulnerability is fixed in Nuclei v3.10.0. Upgrading is strongly recommended.
• Fix reference: https://github.com/projectdiscovery/nuclei/pull/7489

Mitigation

Upgrade to Nuclei v3.10.0, where template execution requirements (including the -file gate) are enforced consistently across the main loader, workflow parsing, and request compilation paths.

In the meantime, avoid running workflows from unverified sources.

Workarounds

If upgrading is not an option, do not run untrusted workflow files. There is no configuration flag that mitigates this bypass on affected versions.

Acknowledgments

Thanks to @daffainfo for reporting this issue.