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Microsoft Security Response CenterCVE-2026-21715

A flaw in Node.js Permission Model filesystem enforcement leaves `fs.realpathSync.native()` without the required read permission checks, while all comparable filesystem functions correctly enforce them. As a result, code running under `--permission` with restricted `--allow-fs-read` can still use `fs.realpathSync.native()` to check file existence, resolve symlink targets, and enumerate filesystem paths outside of permitted directories. This vulnerability affects **20.x, 22.x, 24.x, and 25.x** processes using the Permission Model where `--allow-fs-read` is intentionally restricted.

Mariner

3.3CVSS out of 10Low severity
Scope

What the vendor says is affected

  • azl3 nodejs 20.14.0-14 on Azure Linux 3.0
  • azl3 nodejs24 24.13.0-3 on Azure Linux 3.0

Versions the vendor lists as fixed

  • 20.14.0-15
  • 24.14.1-1
Next step

What the vendor recommends

CBL-Mariner Releases

Review the complete instructions on the vendor's site
Timeline

When this advisory changed

  1. Published by Microsoft Security Response Center

    The publication date reported by the vendor.

  2. Updated by Microsoft Security Response Center

    The vendor changed the advisory after it was first published.

  3. Added to SecurityAlert

    We collected the advisory from the official source.

  4. Confirmed at the source

    Our collector saw this advisory during a later source check.

Vulnerabilities

CVEs named in this advisory