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Fencer Vulns
high 8.3

CVE-2026-44966 json

Velocity.js: Prototype Pollution in #set path assignment

published 2026-05-09 6 mo ago modified 2026-07-24 3 mo ago also GHSA-j658-c2gf-x6pq , EUVD-2026-32007

cvss
8.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 45%
public exploits
0
none known

Summary

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 Velocity templates. If an application renders a template controlled by an attacker, it is possible to modify Object.prototype, potentially leading to Denial of Service (DoS) or Remote Code Execution (RCE) depending on the server environment.

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
5 mo ago

Exploit prediction

0.55% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/shepherdwind/velocity.js/security/advisories/GHSA-j658-c2gf-x6pq referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 8.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
GitHub 3.1 8.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L

Affected packages

ecosystem package affected fixed in
npm velocityjs
<=2.1.5
 no fix listed

Affected products

  • shepherdwind velocity.js

Classification

Weakness
  • CWE-1321 Improperly Controlled Modification of Object Prototype Attributes

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.