Log injection in Rack

1) Improper Output Neutralization for Logs

EUVDB-ID: #VU105795

Risk: Medium

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2025-27111

CWE-ID: CWE-117 - Improper Output Neutralization for Logs

Exploit availability: No

Description

The vulnerability allows a remote attacker to manipulate log entries.

The vulnerability exists due to improper input validation of the X-Sendfile-Type header in Rack::Sendfile when handling. A remote attacker can send specially crafted data containing newline characters via the affected header and manipulate log files.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Rack: 2.2.0 - 3.1.10

CPE2.3

• cpe:2.3:a:rack:rack:2.2.0:*:*:*:*:ruby:*:*
• cpe:2.3:a:rack:rack:2.2.1:*:*:*:*:ruby:*:*
• cpe:2.3:a:rack:rack:2.2.2:*:*:*:*:ruby:*:*
• cpe:2.3:a:rack:rack:2.2.3:*:*:*:*:ruby:*:*
• cpe:2.3:a:rack:rack:2.2.3.1:*:*:*:*:ruby:*:*
• cpe:2.3:a:rack:rack:2.2.4:*:*:*:*:ruby:*:*
• cpe:2.3:a:rack:rack:2.2.5:*:*:*:*:ruby:*:*
• cpe:2.3:a:rack:rack:2.2.6:*:*:*:*:ruby:*:*
• cpe:2.3:a:rack:rack:2.2.6.1:*:*:*:*:ruby:*:*
• cpe:2.3:a:rack:rack:2.2.6.2:*:*:*:*:ruby:*:*

External links

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

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.