What is CVE-2026-44966?

CVE-2026-44966 is a high-severity vulnerability in Shepherdwind Velocity.js, classified under Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution). CVSS score: 8.3/10. Published 2026-05-26.

How severe is CVE-2026-44966?

High severity. CVSS v3 base score is 8.3 out of 10.

Prototype Pollution in Shepherdwind Velocity.js

CVE-2026-44966

Velocity.js is a JavaScript implementation of the Apache Velocity template engine. In 2.1.5 and earlier, a prototype pollution vulnerability was discovered in velocityjs. This issue occurs during the processing of #set directives in Veloci…

Vulnerability class: Prototype Pollution

EPSS: 0.001 (27.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.3 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L.

Affected products

Shepherdwind Velocity.js — versions <= 2.1.5

Weakness classification (CWE)

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

References

security-advisories@github.com (x_refsource_CONFIRM, Exploit, Vendor Advisory)

Frequently asked questions

What is CVE-2026-44966?: CVE-2026-44966 is a high-severity vulnerability in Shepherdwind Velocity.js, classified under Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution). CVSS score: 8.3/10. Published 2026-05-26.
How severe is CVE-2026-44966?: High severity. CVSS v3 base score is 8.3 out of 10.