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CVE-2025-27111: Escape Sequence Injection vulnerability in Rack lead to Possible Log Injection

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.8% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-03-04 · updated 2026-06-17
• Weakness: CWE-93

Description

Rack is a modular Ruby web server interface. The Rack::Sendfile middleware logs unsanitised header values from the X-Sendfile-Type header. An attacker can exploit this by injecting escape sequences (such as newline characters) into the header, resulting in log injection. This vulnerability is fixed in 2.2.12, 3.0.13, and 3.1.11.

Affected products

• rack: before 2.2.12; from 3.0.0 before 3.0.13; from 3.1.0 before 3.1.11 — fixed in 2.2.12, 3.0.13, 3.1.11
• Rubygems Rack: before 2.2.12; from 3.0 before 3.0.13; from 3.1 before 3.1.11; 0.1.0, 0.2.0, 0.3.0, 0.4.0, 0.9.0, 0.9.1 (+134) — fixed in 2.2.12, 3.0.13, 3.1.11

How to fix

Upgrade to a fixed version: rack 2.2.12, 3.0.13, 3.1.11; Rubygems Rack 2.2.12, 3.0.13, 3.1.11. Check the vendor advisory for mitigations.

References

• https://github.com/rack/rack/commit/803aa221e8302719715e224f4476e438f2531a53
• https://github.com/rack/rack/commit/aeac570bb8080ca7b53b7f2e2f67498be7ebd30b
• https://github.com/rack/rack/commit/b13bc6bfc7506aca3478dc5ac1c2ec6fc53f82a3
• https://github.com/rack/rack/security/advisories/GHSA-8cgq-6mh2-7j6v
• https://lists.debian.org/debian-lts-announce/2025/03/msg00016.html

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