In Twisted Web through 19.10.0, there was an HTTP request splitting vulnerability. When presented with two content-length headers, it ignored the first header. When the second content-length value was set to zero, the request body was interpreted as a pipelined request.
https://know.bishopfox.com/advisories/twisted-version-19.10.0
https://know.bishopfox.com/advisories
https://usn.ubuntu.com/4308-1/
https://usn.ubuntu.com/4308-2/
https://security.gentoo.org/glsa/202007-24
https://www.oracle.com/security-alerts/cpuoct2020.html
https://lists.debian.org/debian-lts-announce/2022/02/msg00021.html
Source: MITRE
Published: 2020-03-12
Updated: 2022-04-01
Type: CWE-444
Base Score: 7.5
Vector: AV:N/AC:L/Au:N/C:P/I:P/A:P
Impact Score: 6.4
Exploitability Score: 10
Severity: HIGH
Base Score: 9.8
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Impact Score: 5.9
Exploitability Score: 3.9
Severity: CRITICAL