CVE-2026-39243 Affecting mcp-mongodb package, versions <3.1.0-r0


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.3% (23rd percentile)

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  • Snyk IDSNYK-MINIMOSLATEST-MCPMONGODB-21176959
  • published18 Oct 2026
  • disclosed9 Jul 2026

Introduced: 9 Jul 2026

CVE-2026-39243  (opens in a new tab)

How to fix?

Upgrade Minimos:latest mcp-mongodb to version 3.1.0-r0 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream mcp-mongodb package and not the mcp-mongodb package as distributed by Minimos. See How to fix? for Minimos:latest relevant fixed versions and status.

decompress before 4.2.2 allows arbitrary hardlink creation during archive extraction, enabling file read disclosure and file corruption. When processing hardlink entries (type === 'link'), the x.linkname field from the archive is passed directly to fs.link() without validation (index.js line 113). An attacker can craft an archive with a hardlink entry whose linkname is an absolute path to any file on the same filesystem. This creates a hardlink inside the extraction directory that shares the same inode as the target file, enabling both reading and overwriting the original file's content. Hardlinks are limited to files on the same filesystem and cannot target directories.

CVSS Base Scores

version 3.1