CVE-2026-76803

A vulnerability in Nuclei's JavaScript MySQL client library allows arbitrary local file reads that bypass the `-allow-local-file-access` (`-lfa`) sandbox restriction. **Affected Component** The issue is in the `nuclei/mysql` JavaScript library used by `javascript:` protocol templates. The MySQL client connection logic did not enforce the local file access sandbox when handling the `allowAllFiles` DSN parameter used by `LOAD DATA LOCAL INFILE`. **Description** Without `-lfa`, Nuclei confines local file access to the templates directory. However, a `javascript:` template could connect to a MySQL server with `allowAllFiles=true` in the connection DSN. With this option enabled, a malicious MySQL server can issue `LOAD DATA LOCAL INFILE` requests for arbitrary paths on the scanner host. The MySQL client reads the full file contents and sends them to the server, bypassing the same sandbox that blocks direct filesystem reads through other APIs. `javascript:` templates execute without the `-code` flag and unsigned `javascript:` templates run by default, making this reachable from untrusted third-party templates when scanning attacker-controlled MySQL endpoints. > [!NOTE] The `-allow-local-file-access` (`-lfa`) option is off by default. This issue allows bypassing that restriction, not merely expanding an already-enabled capability. **Affected Users** - **CLI users** running untrusted or third-party `javascript:` templates against MySQL-compatible targets. - **SDK users** who integrate Nuclei into platforms where end users can supply JavaScript templates and rely on the default `-lfa` restriction to limit filesystem access. **Patches** - The vulnerability is fixed in Nuclei v3.10.0. Upgrading is strongly recommended. - Fix reference: https://github.com/projectdiscovery/nuclei/pull/7473 **Mitigation** Upgrade to Nuclei v3.10.0, where the `allowAllFiles` DSN option is stripped unless `-lfa` is explicitly enabled. In the meantime, avoid running JavaScript templates