Cross-site scripting (XSS) in Apache Velocity Tools

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2020-13959: 5.72% estimated exploitation activity in the next 30 days; percentile 93.05 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

The default error page for VelocityView in Apache Velocity Tools prior to 3.1 reflects back the vm file that was entered as part of the URL. An attacker can set an XSS payload file as this vm file in the URL which results in this payload being executed. XSS vulnerabilities allow attackers to execute arbitrary JavaScript in the context of the attacked website and the attacked user. This can be abused to steal session cookies, perform requests in the name of the victim or for phishing attacks.

Published by the source

12 Mar 2021, 20:24 UTC

Last modified by the source

1 Feb 2023, 05:05 UTC

Source last checked

26 Oct 2026, 16:06 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-fh63-4r66-jc7v

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# Patch Next advisory brief: CVE-2020-13959

Advisory: Cross-site scripting (XSS) in Apache Velocity Tools
IDs: CVE-2020-13959, GHSA-fh63-4r66-jc7v
Record: https://patchnext.com/advisories/cve-2020-13959 (revision 1, source checked 26 Oct 2026, 16:06 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Partial vendor fix; fixed versions by package: org.apache.velocity.tools:velocity-tools-parent 3.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven org.apache.velocity.tools:velocity-tools-parent: affected < 3.1; fixed in 3.1
- Maven org.apache.velocity:velocity-tools: affected <= 2.0

## Suggested inspection (read-only)
- Maven org.apache.velocity.tools:velocity-tools-parent: check the installed version with your package manager.
- Maven org.apache.velocity:velocity-tools: check the installed version with your package manager.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on org.apache.velocity.tools:velocity-tools-parent, org.apache.velocity:velocity-tools.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-fh63-4r66-jc7v (GitHub-reviewed advisory GHSA-fh63-4r66-jc7v lists affected ranges: Maven org.apache.velocity.tools:velocity-tools-parent >=0 =0 <=2.0)

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