In Ktor before 1.3.0, request smuggling is possible when running behind a proxy that doesn't handle Content-Length and Transfer-Encoding properly or doesn't handle \n as a headers separator.
https://github.com/ktorio/ktor/security/advisories/GHSA-xrr9-rh8p-433v
https://github.com/ktorio/ktor/pull/1547
Source: Mitre, NVD
Published: 2020-01-27
Updated: 2026-06-17
Base Score: 5
Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:P/A:N
Severity: Medium
Base Score: 7.5
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Severity: High
EPSS: 0.00003