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HIGH

CVE-2026-86439

CVSS v3

8.8

HIGH

EPSS Score

1.1 %

exploit probability, as of 2026-09-25

CISA KEV

No

known exploited

Exploitation

—

SSVC status

Description

knowns versions before 0.30.0 fail to validate filesystem paths in MCP tool arguments, allowing attackers to read, create, overwrite and delete files outside the project directory. Attackers can supply path arguments containing directory traversal sequences to access arbitrary Markdown files accessible to the server process.

Technical details

Published
2026-09-07
Last Modified
2026-09-08

Frequently asked questions

What is CVE-2026-86439?

knowns versions before 0.30.0 fail to validate filesystem paths in MCP tool arguments, allowing attackers to read, create, overwrite and delete files outside the project directory. Attackers can supply path arguments containing directory traversal sequences to access arbitrary Markdown files accessible to the server process.

Is CVE-2026-86439 actively exploited?

Active exploitation of CVE-2026-86439 has not been confirmed. Its EPSS score was 1.1% on 2026-09-25, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-86439?

CVE-2026-86439 has a CVSS v3 base score of 8.8 (HIGH severity).

Is CVE-2026-86439 affecting your environment?

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