Field Test CSRF vulnerability

Exploitation

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

CVSS

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

EPSS

• CVE-2020-16252: 0.43% estimated exploitation activity in the next 30 days; percentile 36.95 (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 Field Test dashboard is vulnerable to cross-site request forgery (CSRF) with non-session based authentication methods in versions v0.2.0 through v0.3.2. Impact The Field Test dashboard is vulnerable to CSRF with non-session based authentication methods, like basic authentication. Session-based authentication methods (like Devise's default authentication) are not affected. A CSRF attack works by getting an authorized user to visit a malicious website and then performing requests on behalf of the user. In this instance, a single endpoint is affected, which allows for changing the variant assigned to a user. All users running an affected release should upgrade immediately. Technical Details Field Test uses the protectfromforgery method from Rails to prevent CSRF. However, this defaults to :nullsession, which has no effect on non-session based authentication methods. This has been changed to protectfromforgery with: :exception.

Published by the source

5 Aug 2020, 14:53 UTC

Last modified by the source

5 Jul 2023, 20:19 UTC

Source last checked

26 Oct 2026, 15:47 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-w542-cpp9-r3g7

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# Patch Next advisory brief: CVE-2020-16252

Advisory: Field Test CSRF vulnerability
IDs: CVE-2020-16252, GHSA-w542-cpp9-r3g7
Record: https://patchnext.com/advisories/cve-2020-16252 (revision 1, source checked 26 Oct 2026, 15:47 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 4.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: field_test 0.4.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- RubyGems field_test: affected >= 0.2.0, <= 0.3.2; fixed in 0.4.0

## Suggested inspection (read-only)
- RubyGems field_test: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on field_test.
- 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-w542-cpp9-r3g7 (GitHub-reviewed advisory GHSA-w542-cpp9-r3g7 lists affected ranges: RubyGems field_test >=0.2.0 <=0.3.2)

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