CVE-2022-30123

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

Or

use Rack::CommonLogger

All users running an affected release should either upgrade or use one of the
workarounds immediately.

Workarounds

Remove these middleware from your application

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:

use Rack::Lint

CVE-2022-30123 has a CVSS score of 10.0 (Critical). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2.0.9.1, 2.1.4.1, 2.2.3.1); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2022-30123? CVE-2022-30123 is a critical-severity security vulnerability in rack (rubygems), affecting versions <= 2.0.9.0. It is fixed in 2.0.9.1, 2.1.4.1, 2.2.3.1.
2. How severe is CVE-2022-30123? CVE-2022-30123 has a CVSS score of 10.0 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of rack are affected by CVE-2022-30123? rack (rubygems) versions <= 2.0.9.0 is affected.
4. Is there a fix for CVE-2022-30123? Yes. CVE-2022-30123 is fixed in 2.0.9.1, 2.1.4.1, 2.2.3.1. Upgrade to this version or later.
5. Is CVE-2022-30123 exploitable, and should I be worried? Whether CVE-2022-30123 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2022-30123 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2022-30123?
   • Upgrade rack to 2.0.9.1 or later
   • Upgrade rack to 2.1.4.1 or later
   • Upgrade rack to 2.2.3.1 or later