CVE-2026-40576
Unauthenticated path traversal in excel-mcp-server allows file read/write via MCP handlers.
Is CVE-2026-40576 being exploited?
Not confirmed. CVE-2026-40576 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.39% probability of exploitation in the next 30 days.
How severe is CVE-2026-40576?
CVE-2026-40576 is rated Critical with a CVSS score of 9.4. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-40576?
Yes. A fix has been recorded for CVE-2026-40576. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-40576 affect?
CVE-2026-40576 affects excel-mcp-server ≤0.1.7. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-40576?
Upgrade to 0.1.8+; apply patch; limit network exposure
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote attacker can read, write, or overwrite arbitrary host files via crafted paths on an unauthenticated transport.
Immediate action required
- affected< 0.1.8
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.