CVE-2019-16254: Debian Linux

Medium severity, CVSS 5.3. EPSS: 4.6% chance of exploitation in the next 30 days.

Ruby through 2.4.7, 2.5.x through 2.5.6, and 2.6.x through 2.6.4 allows HTTP Response Splitting. If a program using WEBrick inserts untrusted input into the response header, an attacker can exploit it to insert a newline character to split a header, and inject malicious content to deceive clients. NOTE: this issue exists because of an incomplete fix for CVE-2017-17742, which addressed the CRLF vector, but did not address an isolated CR or an isolated LF.

Affected products

• Debian Debian Linux: version 8.0 only
• Ruby-Lang Ruby: up to and including 2.3.0; from 2.4.0, up to and including 2.4.7; from 2.5.0, up to and including 2.5.6; from 2.6.0, up to and including 2.6.4

Published 2019-11-26. Last modified 2026-06-17.