Velocity.js: Prototype Pollution in #set path assignment
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and GitHub.
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| shepherdwind | velocity.js | up to 2.1.5 | — | No fix listed | CNA |
| — | velocityjs (npm) | up to 2.1.5 | — | No fix listed | GHSA-j658-c2gf-x6pq |
- velocity.js Vendorshepherdwind Affected up to 2.1.5 Fixed in — No fix listed CNA
- velocityjs (npm) Vendor— Affected up to 2.1.5 Fixed in — No fix listed GHSA-j658-c2gf-x6pq
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:shepherdwind:velocity.js:*:*:*:*:*:node.js:*:* | up to 2.1.5 | Vulnerable | shepherdwind |
- cpe:2.3:a:shepherdwind:velocity.js:*:*:*:*:*:node.js:*:* Versions up to 2.1.5 Vulnerable ·shepherdwind
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2026-44966
- 2026-10-03 Alias added: GHSA-j658-c2gf-x6pq
References
Sources
- CVE-2026-44966 · CVE Program
- CVE-2026-44966 · NVD
- FIRST EPSS
- GHSA-j658-c2gf-x6pq · GitHub Advisory Database · CC BY 4.0
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