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CVE-2026-44966: Shepherdwind Velocity.Js Prototype Pollution (CVSS 8.3)

CVE-2026-44966 is a high severity prototype pollution in Shepherdwind Velocity.Js with a CVSS score of 8.3. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

Last updated: Jul 24, 2026

Quick answer

Direct answer

CVE-2026-44966 is a high severity prototype pollution in Shepherdwind Velocity.Js with a CVSS score of 8.3. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

Risk scores

CVSS base score
8.3HIGH
EPSS probability
0.61%
Higher than 48 percent of all CVEs
CISA KEV
Not listed
CVSS metricWhat it means
Attack vector (AV:N)Network: reachable remotely
Attack complexity (AC:L)Low complexity
Privileges required (PR:N)No privileges required
User interaction (UI:N)No user interaction
Scope (S:C)Scope changed: impact spreads beyond the component
Confidentiality (C:L)Low confidentiality impact
Integrity (I:L)Low integrity impact
Availability (A:L)Low availability impact

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L

About Shepherdwind Velocity.Js

CVE-2026-44966 affects Shepherdwind Velocity.Js, a product from Shepherdwind. Before acting, confirm where Shepherdwind Velocity.Js runs in your estate, who owns it and whether it is reachable from the internet, because exposure decides real risk more than the score alone.

What the flaw is

In plain terms: 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.

The weakness class is Prototype Pollution. Attacker input changes the base object of a JavaScript application.

Based on its CVSS vector, the flaw can be reached over the network, needs no login, and needs no user interaction. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

Affected versions and timeline

FieldDetail
ProductShepherdwind Velocity.Js
Affected versionsVelocity.Js up to and including 2.1.5
PublishedMay 26, 2026
Last modifiedJul 24, 2026
Added to CISA KEVNot listed
Assigning CNAsecurity-advisories@github.com

How to detect it

  • Inventory every instance of Shepherdwind Velocity.Js and record the running version against the affected range above.
  • Check external attack surface scans for internet facing instances of the component.
  • Review logs on affected systems for unusual requests, errors or new processes around the vulnerable function.
  • Confirm with an authenticated vulnerability scan once your scanner has a check for this CVE.

How to fix it

  • Apply the fixed version of Shepherdwind Velocity.Js named in the vendor advisory.
  • If patching must wait, restrict network access to the affected service and put it behind authentication or a web application firewall rule.
  • Rescan after the change to prove the exposure is gone, then close the ticket.

CTEM action plan

CTEM stageWhat to do for this CVE
ScopeAdd every business service that depends on Shepherdwind Velocity.Js to the current CTEM cycle.
DiscoverFind all instances, including shadow and cloud deployments, and record versions and exposure.
PrioritizeRank using EPSS and CVSS together with asset exposure and business impact.
ValidateConfirm the flaw is reachable and exploitable in your environment and that compensating controls work.
MobilizeAssign the fix to the asset owner with a due date matched to the priority, then verify closure.

CWE References

Technical References

Frequently asked questions

CVE-2026-44966 is a high severity prototype pollution in Shepherdwind Velocity.Js with a CVSS score of 8.3. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

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