Vulnerability Details CVE-2026-27171
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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.002
EPSS Ranking 10.3%
CVSS Severity
CVSS v3 Score 2.9
References
- https://7asecurity.com/blog/2026/02/zlib-7asecurity-audit/
- https://7asecurity.com/reports/pentest-report-zlib-RC1.1.pdf
- https://github.com/madler/zlib/issues/904
- https://github.com/madler/zlib/releases/tag/v1.3.2
- https://ostif.org/zlib-audit-complete/
- https://7asecurity.com/reports/pentest-report-zlib-RC1.1.pdf