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.
Exploitability
AV:NAC:LPR:NUI:NScope
S:UImpact
C:NI:HA:N7.5/CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:NOther