CVE-2026-21716

Description

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.

CVSS Metrics

• v3.0•LOW•Score: 3.3CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

EPSS Trends

Current EPSS score: 0.15%• Percentile: 4%

Techniques & Countermeasures

• CWE-862•Missing Authorization

  The product does not perform an authorization check when an actor attempts to access a resource or perform an action.

Affected Systems

• alpine•nodejs

  < 22.22.2-r0 | < 22.22.2-r0 | < 24.14.1-r0 | < 24.14.1-r0

• chainguard•nodejs-16

  all

• chainguard•nodejs-18

  all

• chainguard•nodejs-21

  all

• chainguard•nodejs-22

  < 22.22.3-r0

• chainguard•nodejs-23

  all

• wolfi•nodejs-16

  all

• wolfi•nodejs-18

  all

• wolfi•nodejs-21

  all

• wolfi•nodejs-22

  < 22.22.3-r0

• wolfi•nodejs-23

  all

• debian•nodejs

  < 20.19.2+dfsg-1+deb13u2 | < 22.22.2+dfsg+~cs22.19.15-1

• nodejs•node

  20.20.1 | 22.22.1 | 24.14.0 | 25.8.1

• nodejs•node.js

  ≤ 20.20.1 | ≥ 22.0.0, ≤ 22.22.1 | ≥ 24.0.0, ≤ 24.14.0 | ≥ 25.0.0, ≤ 25.8.1

References (5)

• https://nodejs.org/en/blog/vulnerability/march-2026-security-releases
• https://security-tracker.debian.org/tracker/CVE-2026-21716
• https://security.alpinelinux.org/vuln/CVE-2026-21716
• https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/21xxx/CVE-2026-21716.json
• https://nvd.nist.gov/vuln/detail/CVE-2026-21716