Velocity.js has a Prototype Pollution vulnerability through #set path assignment
### Summary A prototype pollution vulnerability was discovered in Velocity.js )[key] = val`. Because there is no validation or filtering to block sensitive keys such as \_\_proto\_\_, constructor, or prototype, an attacker can traverse the prototype chain and pollute the global Object.prototype. ### PoC ```javascript const {render} = require('veloc...
CVSS 8.3 MEDIUM. SENTINEL APEX recommends immediate patch evaluation. Intelligence from 1 confirmed source(s).
📋 Executive Summary
This report analyzes CVE-2026-44966 affecting npm velocityjs. Composite threat score: 46/100. Intelligence corroborated across 1 source(s): github_advisories. CVSS base score: 8.3. No confirmed in-the-wild exploitation at the time of writing; prioritize on exposure, privilege, and CVSS.
⚠️ Business Impact Analysis
- ⚠️ npm velocityjs users face material security risk requiring immediate remediation
🔗 Representative Attack Path
A typical attack path for this vulnerability class, mapped to MITRE ATT&CK — a representative model to guide detection and defense, not a claim of observed activity against a specific target. Confirm specifics against the primary sources below.
| # | Phase | Attacker Action | MITRE |
|---|---|---|---|
1 |
Reconnaissance | Attacker identifies exposed velocityjs instances via Shodan, Censys, or targeted scanning | TA0043 |
2 |
Initial Access | Exploitation of CVE-2026-44966 in npm velocityjs | T1190 |
3 |
Persistence | Backdoor, scheduled task, or new admin account created for persistent access | T1053 |
4 |
Command & Control | Attacker establishes persistent C2 channel using HTTPS or DNS tunneling | T1071 |
5 |
Impact / Objectives | Intellectual property theft, espionage, cryptomining, or preparation for future attack stage | T1657 |
⚠ Deep Dive Analysis
This high-severity vulnerability in npm velocityjs (CVSS 8.3) represents a significant attack surface. SENTINEL APEX assesses exploitation to be technically feasible with moderate effort. Organizations running velocityjs in internet-facing or privileged positions face immediate risk.
SENTINEL APEX URGENCY: HIGH. Score: 46/100 MEDIUM. Patch before exploitation activity begins.
🎯 MITRE ATT&CK Mapping
| Category | Mapping |
|---|---|
| Primary Tactic | Initial Access |
| Primary Technique | T1190 — Exploit Public-Facing Application |
| Sub-Technique | T1203 — Exploitation for Client Execution |
| Weakness (CWE) | CWE-1321 |
| Intel Type | 🔴 CVE ANALYSIS |
| Source(s) | github_advisories |
🔴 CVE Reference
| CVE ID | Reference | Score |
|---|---|---|
| CVE-2026-44966 | NVD → | 8.3 |
| CVE-2026-44966 | NVD → | 8.3 |
🔍 Detection Rules — Sigma (SIEM)
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📡 Detection Rules — YARA (Endpoint)
Deploy to endpoint detection platforms. Enterprise subscribers receive tuned, FP-validated YARA rule packs.
🛡️ SOC Response Playbook
- 1IMMEDIATE (0-1hr): Identify all instances of velocityjs in your environment via CMDB/asset inventory
- 2IMMEDIATE (0-1hr): Apply vendor patch — no maintenance window exception for MEDIUM threats
- 3IMMEDIATE (1-2hr): If no patch available: implement WAF rules, ACLs, or network-level compensating controls
- 4SHORT-TERM (2-4hr): Deploy Sigma detection rule to SIEM — validate alert generation in test environment
- 5SHORT-TERM (4-8hr): Review logs for exploitation indicators (anomalous velocityjs requests, error spikes)
- 6SHORT-TERM (8-24hr): Hunt for post-exploitation: new admin accounts, scheduled tasks, lateral movement
- 7MONITOR: Subscribe to npm security advisories for patch updates
- 8ONGOING: Track SENTINEL APEX intelligence feed for follow-on campaigns targeting velocityjs
📎 Intelligence References
- github.com/advisories/GHSA-j658-c2gf-x6pq
- github.com/shepherdwind/velocity.js/security/advisories/GHSA-j658-c2gf
- github.com/advisories/GHSA-j658-c2gf-x6pq
- 📌 NVD — CVE-2026-44966
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Report ID: SENTINEL-CVE-2026-44966-2026-05-09 | Priority: 46/100 MEDIUM | Sources: 1
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