An issue was discovered in Squid through 4.13 and 5.x through 5.0.4. Due to improper input validation, it allows a trusted client to perform HTTP Request Smuggling and access services otherwise forbidden by the security controls. This occurs for certain uri_whitespace configuration settings.
Exploitability
AV:NAC:LPR:NUI:NScope
S:CImpact
C:HI:NA:N8.6/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N