Possible Log Injection in Rack::CommonLogger

Exploitation

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

CVSS 4.0

5.7 · CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P · score source

EPSS

• CVE-2025-25184: 1.19% estimated exploitation activity in the next 30 days; percentile 67.88 (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.

Summary Rack::CommonLogger can be exploited by crafting input that includes newline characters to manipulate log entries. The supplied proof-of-concept demonstrates injecting malicious content into logs. Details When a user provides the authorization credentials via Rack::Auth::Basic, if success, the username will be put in env['REMOTEUSER'] and later be used by Rack::CommonLogger for logging purposes. The issue occurs when a server intentionally or unintentionally allows a user creation with the username contain CRLF and white space characters, or the server just want to log every login attempts. If an attacker enters a username with CRLF character, the logger will log the malicious username with CRLF characters into the logfile. Impact Attackers can break log formats or insert fraudulent entries, potentially obscuring real activity or injecting malicious data into log files. Mitigation - Update to the latest version of Rack.

Published by the source

12 Feb 2025, 19:18 UTC

Last modified by the source

4 Nov 2025, 00:32 UTC

Source last checked

26 Oct 2026, 15:51 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-7g2v-jj9q-g3rg

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# Patch Next advisory brief: CVE-2025-25184

Advisory: Possible Log Injection in Rack::CommonLogger
IDs: CVE-2025-25184, GHSA-7g2v-jj9q-g3rg
Record: https://patchnext.com/advisories/cve-2025-25184 (revision 1, source checked 26 Oct 2026, 15:51 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: rack 3.1.10, 3.0.12, 2.2.11. A vendor fix does not mean a deployment is fixed.

## Affected components
- RubyGems rack: affected < 2.2.11; >= 3.0, < 3.0.12; >= 3.1, < 3.1.10; fixed in 2.2.11, 3.1.10, 3.0.12

## 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-7g2v-jj9q-g3rg (GitHub-reviewed advisory GHSA-7g2v-jj9q-g3rg lists affected ranges: RubyGems rack >=0 =3.0 =3.1 <3.1.10)

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