CVE-2025-67366 sylphxltd CVE debrief

Who should care

Defenders responsible for systems using the @sylphxltd/filesystem-mcp package should assess exposure and prioritize verification and mitigation. This includes reviewing the vulnerability's impact on their systems, applying patches or mitigations as needed, and monitoring for potential exploitation attempts. Security teams and vulnerability management teams should also be aware of the potential risks and take necessary actions.

Why it matters

CVE-2025-67366 is a high-severity path traversal vulnerability in @sylphxltd/filesystem-mcp. Defenders should prioritize verifying the vulnerability's impact on their systems and applying patches or mitigations as needed.

• Verify vulnerability impact on systems
• Apply patches or mitigations as needed
• Monitor for potential exploitation attempts

Technical summary

The @sylphxltd/filesystem-mcp package contains a critical path traversal vulnerability in its 'read_content' tool. The vulnerability arises from improper symlink handling in the path validation mechanism, allowing attackers to bypass directory restrictions and access files outside the intended operational scope. This issue is particularly severe due to the high CVSS score of 7.5, indicating high severity. The vulnerability can be exploited by leveraging symlinks within the allowed directory that point to external files.

Defensive priority

Defenders should prioritize verifying the vulnerability's impact on their systems and applying patches or mitigations as needed.

Recommended defensive actions

• Verify the vulnerability's impact on your systems
• Apply patches or mitigations as needed
• Monitor for potential exploitation attempts
• Review compensating controls for exposed systems
• Check relevant monitoring, detection, and logs for exposed assets
• Track exceptions and retest remediated assets
• Review the supplied official advisory or CVE record to validate affected scope and severity

Evidence notes

The vulnerability is described in the CVE record and NVD vulnerability detail page. The product reference is available on GitHub. Additional information can be found in the official CVE Program record and NIST NVD detail page. The CVE record was published on 2026-01-07T17:16:01.893Z and has not been modified since then. The NVD vulnerability detail page provides further source-specific vulnerability assessment.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.