When verifying a mac with a ChunkedMacVerification object, Tink compares the resulting tag with non constant time comparison. This potentially allows an attacker to use timinig information as a side channel in order to get information how many bytes of a given tag match the correct tag. This in turn could allow to find a correct tag bytewise.
Exploitability
AV:NAC:HAT:NPR:NUI:NVulnerable System
VC:NVI:HVA:NSubsequent System
SC:NSI:NSA:N8.2/CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:NOther