zlib before 1.3.2 allows CPU consumption via crc32_combine64 and crc32_combine_gen64 because x2nmodp can do right shifts within a loop that has no termination condition.
Exploitability
AV:LAC:HPR:NUI:NScope
S:UImpact
C:NI:NA:L2.9/CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:LOther