Vulnerability in Zlib

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.

EPSS: 0.002 (12.4th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 2.9 (Low). Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-27171?
CVE-2026-27171 is a low-severity vulnerability in Zlib, classified under Improper Validation of Specified Quantity in Input. CVSS score: 2.9/10. Published 2026-02-18.
How severe is CVE-2026-27171?
Low severity. CVSS v3 base score is 2.9 out of 10.