Gunicorn fails to properly validate Transfer-Encoding headers, leading to HTTP Request Smuggling (HRS) vulnerabilities. By crafting requests with conflicting Transfer-Encoding headers, attackers can bypass security restrictions and access restricted endpoints. This issue is due to Gunicorn's handling of Transfer-Encoding headers, where it incorrectly processes requests with multiple, conflicting Transfer-Encoding headers, treating them as chunked regardless of the final encoding specified. This vulnerability allows for a range of attacks including cache poisoning, session manipulation, and data exposure.
https://lists.debian.org/debian-lts-announce/2024/12/msg00018.html
https://lists.debian.org/debian-lts-announce/2024/06/msg00027.html
https://huntr.com/bounties/22158e34-cfd5-41ad-97e0-a780773d96c1
Published: 2024-04-16
Updated: 2024-12-20
Base Score: 8.5
Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:C/A:N
Severity: High
Base Score: 7.5
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Severity: High
Base Score: 6.6
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
Severity: Medium