CVE-2026-27171
MEDIUMCVSS 5.5/10EPSS 0.20%
Last modified
CVE-2026-27171 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. 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 estimates a 0.20% chance of exploitation in the next 30 days.
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.
Metrics
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Zlib | Zlib | >= 1.2.12, < 1.3.2 |
References
- https://7asecurity.com/reports/pentest-report-zlib-RC1.1.pdfTechnical Description
- https://github.com/madler/zlib/issues/904Exploit, Issue Tracking
- https://github.com/madler/zlib/releases/tag/v1.3.2Release Notes
- https://7asecurity.com/reports/pentest-report-zlib-RC1.1.pdfTechnical Description
Timeline
- Published
- Last Modified
- Status
- Analyzed
Frequently Asked Questions
What is 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.
How severe is CVE-2026-27171?
CVE-2026-27171 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.20% probability of exploitation in the next 30 days.
How do I fix CVE-2026-27171?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.
Are you affected by CVE-2026-27171?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST