Injection in MockServer

Exploitation

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

CVSS

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

EPSS

• CVE-2021-32827: 2.16% estimated exploitation activity in the next 30 days; percentile 82.26 (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.

MockServer is open source software which enables easy mocking of any system you integrate with via HTTP or HTTPS. An attacker that can trick a victim into visiting a malicious site while running MockServer locally, will be able to run arbitrary code on the MockServer machine. With an overly broad default CORS configuration MockServer allows any site to send cross-site requests. Additionally, MockServer allows you to create dynamic expectations using Javascript or Velocity templates. Both engines may allow an attacker to execute arbitrary code on-behalf of MockServer. By combining these two issues (Overly broad CORS configuration + Script injection), an attacker could serve a malicious page so that if a developer running MockServer visits it, they will get compromised. For more details including a PoC see the referenced GHSL-2021-059.

Published by the source

30 Aug 2021, 16:24 UTC

Last modified by the source

27 Jan 2023, 05:00 UTC

Source last checked

26 Oct 2026, 15:53 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-v3cg-h3f6-2242

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# Patch Next advisory brief: CVE-2021-32827

Advisory: Injection in MockServer
IDs: CVE-2021-32827, GHSA-v3cg-h3f6-2242
Record: https://patchnext.com/advisories/cve-2021-32827 (revision 1, source checked 26 Oct 2026, 15:53 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: Vendor response not established. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven org.mock-server:mockserver: affected <= 5.11.2

## Suggested inspection (read-only)
- Maven org.mock-server:mockserver: 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.mock-server:mockserver.
- 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-v3cg-h3f6-2242 (GitHub-reviewed advisory GHSA-v3cg-h3f6-2242 lists affected ranges: Maven org.mock-server:mockserver >=0 <=5.11.2)

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