Node.js FileHandle Promise API Bypass in PermissionModel
CVE-2026-21716 Published on March 30, 2026
An incomplete fix for CVE-2024-36137 leaves `FileHandle.chmod()` and `FileHandle.chown()` in the promises API without the required permission checks, while their callback-based equivalents (`fs.fchmod()`, `fs.fchown()`) were correctly patched. As a result, code running under `--permission` with restricted `--allow-fs-write` can still use promise-based `FileHandle` methods to modify file permissions and ownership on already-open file descriptors, bypassing the intended write restrictions. This vulnerability affects **20.x, 22.x, 24.x, and 25.x** processes using the Permission Model where `--allow-fs-write` is intentionally restricted.
Weakness Type
What is an AuthZ Vulnerability?
The software does not perform an authorization check when an actor attempts to access a resource or perform an action.
CVE-2026-21716 has been classified to as an AuthZ vulnerability or weakness.
Affected Versions
nodejs node:- Version 20.20.1, <= 20.20.1 is affected.
- Version 22.22.1, <= 22.22.1 is affected.
- Version 24.14.0, <= 24.14.0 is affected.
- Version 25.8.1, <= 25.8.1 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.