guzzlehttp/guzzle versions before 7.15.1 fail to preserve host-only cookie scope, storing the request host in the Domain field instead of marking cookies as host-only. Attackers controlling child hosts can receive host-only cookies intended only for parent hosts, potentially disclosing session identifiers and authorization tokens when the same cookie jar is reused across trust boundaries.
Exploitability
AV:NAC:HAT:PPR:NUI:NVulnerable System
VC:HVI:NVA:NSubsequent System
SC:NSI:NSA:N8.2/CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:NOther