Possible shell escape sequence injection vulnerability in Rack

Exploitation

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

CVSS

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

EPSS

• CVE-2022-30123: 1.96% estimated exploitation activity in the next 30 days; percentile 80.29 (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.

There is a possible shell escape sequence injection vulnerability in the Lint and CommonLogger components of Rack. This vulnerability has been assigned the CVE identifier CVE-2022-30123. Versions Affected: All. Not affected: None Fixed Versions: 2.0.9.1, 2.1.4.1, 2.2.3.1 Impact Carefully crafted requests can cause shell escape sequences to be written to the terminal via Rack's Lint middleware and CommonLogger middleware. These escape sequences can be leveraged to possibly execute commands in the victim's terminal. Impacted applications will have either of these middleware installed, and vulnerable apps may have something like this: Or All users running an affected release should either upgrade or use one of the workarounds immediately. Workarounds Remove these middleware from your application

Published by the source

27 May 2022, 16:36 UTC

Last modified by the source

17 Dec 2023, 05:05 UTC

Source last checked

26 Oct 2026, 15:48 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-wq4h-7r42-5hrr

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# Patch Next advisory brief: CVE-2022-30123

Advisory: Possible shell escape sequence injection vulnerability in Rack
IDs: CVE-2022-30123, GHSA-wq4h-7r42-5hrr
Record: https://patchnext.com/advisories/cve-2022-30123 (revision 1, source checked 26 Oct 2026, 15:48 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 10.0)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: rack 2.2.3.1, 2.1.4.1, 2.0.9.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- RubyGems rack: affected <= 2.0.9.0; >= 2.1, <= 2.1.4.0; >= 2.2, <= 2.2.3.0; fixed in 2.2.3.1, 2.1.4.1, 2.0.9.1

## Suggested inspection (read-only)
- RubyGems rack: 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 rack.
- 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-wq4h-7r42-5hrr (GitHub-reviewed advisory GHSA-wq4h-7r42-5hrr lists affected ranges: RubyGems rack >=0 =2.1 =2.2 <=2.2.3.0)

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