Directive injection when using dynamic overrides with user input

Exploitation

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

CVSS

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

EPSS

• CVE-2020-5217: 1.83% estimated exploitation activity in the next 30 days; percentile 78.89 (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.

Impact If user-supplied input was passed into append/overridecontentsecuritypolicydirectives, a semicolon could be injected leading to directive injection. This could be used to e.g. override a script-src directive. Duplicate directives are ignored and the first one wins. The directives in secureheaders are sorted alphabetically so they pretty much all come before script-src. A previously undefined directive would receive a value even if SecureHeaders::OPTOUT was supplied. The fixed versions will silently convert the semicolons to spaces and emit a deprecation warning when this happens. This will result in innocuous browser console messages if being exploited/accidentally used. In future releases, we will raise application errors resulting in 500s. Duplicate script-src directives detected. All but the first instance will be ignored. See https://www.w3.org/TR/CSP3/#parse-serialized-policy Note: In this case, the user agent SHOULD notify developers that a duplicate directive was…

Published by the source

23 Jan 2020, 02:28 UTC

Last modified by the source

16 May 2023, 16:09 UTC

Source last checked

26 Oct 2026, 15:47 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-xq52-rv6w-397c

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# Patch Next advisory brief: CVE-2020-5217

Advisory: Directive injection when using dynamic overrides with user input
IDs: CVE-2020-5217, GHSA-xq52-rv6w-397c
Record: https://patchnext.com/advisories/cve-2020-5217 (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 4.4)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: secure_headers 6.2.0, 5.1.0, 3.8.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- RubyGems secure_headers: affected >= 6.0.0, < 6.2.0; >= 5.0.0, < 5.1.0; < 3.8.0; fixed in 5.1.0, 3.8.0, 6.2.0

## Suggested inspection (read-only)
- RubyGems secure_headers: 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 secure_headers.
- 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-xq52-rv6w-397c (GitHub-reviewed advisory GHSA-xq52-rv6w-397c lists affected ranges: RubyGems secure_headers >=6.0.0 =5.0.0 =0 <3.8.0)

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