What is CVE-2026-53609?

CVE-2026-53609 is a critical-severity vulnerability, classified under Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution). CVSS score: 9.1/10. Published 2026-06-12.

How severe is CVE-2026-53609?

Critical severity. CVSS v3 base score is 9.1 out of 10.

CVE-2026-53609

CVE-2026-53609

ApostropheCMS is an open-source Node.js content management system. In versions up to and including 4.30.0, `apos.util.set()` traverses dot-notation paths without sanitizing `__proto__`, allowing an authenticated editor to write arbitrary v…

Vulnerability class: Prototype Pollution

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L.

Weakness classification (CWE)

CWE-1321 — Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution)

References

security-advisories@github.com

Frequently asked questions

What is CVE-2026-53609?: CVE-2026-53609 is a critical-severity vulnerability, classified under Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution). CVSS score: 9.1/10. Published 2026-06-12.
How severe is CVE-2026-53609?: Critical severity. CVSS v3 base score is 9.1 out of 10.