Home/CVE/zlib before 1.3.2 allows CPU consumption via crc32_combine64 and crc32_combine_gen64 because x2nmodp can do right shifts
CVE

CVE-2026-27171

zlib before 1.3.2 allows CPU consumption via crc32_combine64 and crc32_combine_gen64 because x2nmodp can do right shifts

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.

LOW · CVSS 2.9 EPSS 9e-05
Schedule remediation
  • Public exploit or PoC is available
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-1284Improper Validation of Specified Quantity in Input
▤

Affected Products & Versions

1
zlib>= 1.2.12 and < 1.3.2
⚠

Public Exploits & PoCs

1
pocgithub.com · issues/904github.com
▣

Scoring & Timeline

2.9
LOW · CVSS v3.1 · cve@mitre.org
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD18 Feb 2026 · 04:16 AM
CVSS VectorCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
SSVC triage · cisa-vulnrichment
Exploitation
poc
Automatable
no
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
⚑

Vendor Advisories

9
suse-csafopenSUSE-SU-2026:10617-1
suse-csafopenSUSE-SU-2026:20487-1
suse-csafSUSE-SU-2026:21013-1
suse-csafSUSE-SU-2026:21151-1
suse-csafopenSUSE-SU-2026:10320-1
🔗

References & Sources

4
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://7asecurity.com/blog/2026/02/zlib-7asecurity-audit/Product
https://7asecurity.com/reports/pentest-report-zlib-RC1.1.pdfTechnical Description
https://github.com/madler/zlib/releases/tag/v1.3.2Release Notes
https://ostif.org/zlib-audit-complete/Product
Intelligence Graph · click any node to traverse
CVETechnique ActorTool Family
drag to reposition · click any node to traverse · button top-right enlarges
External lookups - second-class, for what we don’t hold ourselves
NVDCVE.orgCISAVulnersExploit-DBGitHub PoCVulnCheck KEVGreyNoise
Vulnerabilities
CISA KEV catalog
CWE weaknesses
CAPEC attack patterns
Package vulnerabilities
Threat intelligence
Threat actors
Tools & malware
ATT&CK techniques
IOCs
Detection & defense
Sigma rules
YARA rules
Atomic Red Team tests
D3FEND countermeasures
Compliance
NIST 800-53
ISO 27001:2022
SOC 2 TSC
PCI-DSS v4.0
CIS Controls v8.1
About
All capabilities
Live statistics
Data sources
Privacy policy
Terms of service
threatengine.sh  ·  Open-source threat intelligence platform  ·  100+ authoritative sources  ·  Every fact traces to its origin