LOWPOC
CVE-2026-27171
CWE-1284Published: February 18, 2026· Updated: Feb 20, 2026
2.9
CVSS v3.1
EPSS:0.01%probability of exploitation in 30 daysPercentile:0.4th
Official 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.
Technical Analysis
CVE-2026-27171 requires local access, meaning attackers must already have a foothold on the target system.
The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.
A proof-of-concept (PoC) exploit exists for CVE-2026-27171. While not yet confirmed in active campaigns, the availability of PoC code increases exploitation risk substantially.
CVSS v3.1 Vector Breakdown
Exploitability
Attack VectorLocal
Attack ComplexityHigh
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityNone
AvailabilityLow
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
Affected Vendors & Products
zlib1 product
zlib
Source: NVD CPE · 1 total CPE entries
Exploit & PoC Resources
POC AVAILABLEProof-of-concept code exists
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.
All References (6)
→
https://7asecurity.com/reports/pentest-report-zlib-RC1.1.pdfTechnical Description
→
https://github.com/madler/zlib/issues/904Issue Tracking · Exploit
→
https://github.com/madler/zlib/releases/tag/v1.3.2Release Notes
→
https://7asecurity.com/reports/pentest-report-zlib-RC1.1.pdfTechnical Description
Quick Facts
CVE IDCVE-2026-27171
CVSS Score2.9 / 10
SeverityLOW
WeaknessCWE-1284
CISA KEVNo
ExploitPOC
EPSS (30d)0.01%
Affected1 vendor
PublishedFeb 18, 2026
Related CVEs (CWE-1284)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2026-27171 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.