CVE-2026-27171

Description

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.

CVSS breakdown

Affected products

• zlib / zlib0 – 1.3.2

References

• MISChttps://github.com/madler/zlib/issues/904
• MISChttps://7asecurity.com/reports/pentest-report-zlib-RC1.1.pdf
• MISChttps://7asecurity.com/blog/2026/02/zlib-7asecurity-audit/
• MISChttps://ostif.org/zlib-audit-complete/
• PATCHhttps://github.com/madler/zlib/releases/tag/v1.3.2