How severe is CVE-2026-76803?

CVE-2026-76803 has a CVSS score of 5.3/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2026-76803?

CVE-2026-76803 affects the following packages: github.com/projectdiscovery/nuclei/v3 (Go). Ecosystems affected: Go.

How do I fix CVE-2026-76803?

Update github.com/projectdiscovery/nuclei/v3 to 3.10.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-76803 is resolved across your whole dependency graph.

How do I detect CVE-2026-76803 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/projectdiscovery/nuclei/v3, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-76803 if there is no patch (or I can't update yet)?

Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Is CVE-2026-76803 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-76803 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-76803?

CVE-2026-76803 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 33th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-76803?

CVE-2026-76803 is classified as CWE-284 (CWE-284). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-76803 published, and has it been updated?

CVE-2026-76803 was published on September 22, 2026 and was last updated on October 21, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹

🐹 Go

Not in CISA KEV

MEDIUM severity

CVE-2026-76803 — nuclei

MEDIUMFix: projectdiscovery/nuclei@9611926

CVE-2026-76803 is a medium-severity (CVSS 5.3) CWE-284 vulnerability in github.com/projectdiscovery/nuclei/v3. A fix is available for github.com/projectdiscovery/nuclei/v3 — see the affected versions and patch details below.

Nuclei: Local File Read via MySQL Client Sandbox Bypass

Also known asGHSA-xhmx-w2j4-rw3qGO-2026-6577

Published

Sep 22, 2026

Updated

Oct 21, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 22, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-76803.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs33th percentile — riskier than 33% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2026-76803 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 394,803 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected

🐹github.com/projectdiscovery/nuclei/v3

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

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 from unverified sources, especially against untrusted database endpoints.

Workarounds

If upgrading is not an option, avoid running untrusted JavaScript templates. There is no flag or configuration that mitigates this bypass on affected versions.

Acknowledgments

Thanks to @daffainfo for reporting this issue.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/projectdiscovery/nuclei/v3`	≥ 3.0.0&&< 3.10.0	3.10.0`go get github.com/projectdiscovery/nuclei/v3@v3.10.0`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/projectdiscovery/nuclei/v3, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/projectdiscovery/nuclei/v3 to 3.10.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-76803 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Frequently Asked Questions

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 M