CVE-2026-27171
Zlib CPU Consumption Denial of Service
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.
INFO
Published Date :
Feb. 18, 2026, 4:16 a.m.
Last Modified :
Feb. 20, 2026, 4:45 p.m.
Remotely Exploit :
No
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | LOW | 8254265b-2729-46b6-b9e3-3dfca2d5bfca | ||||
| CVSS 3.1 | LOW | [email protected] | ||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update zlib to version 1.3.2 or later.
- Apply vendor patches if available.
- Review code for similar loop constructs.
Public PoC/Exploit Available at Github
CVE-2026-27171 has a 2 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-27171.
| URL | Resource |
|---|---|
| https://7asecurity.com/blog/2026/02/zlib-7asecurity-audit/ | Product |
| https://7asecurity.com/reports/pentest-report-zlib-RC1.1.pdf | Technical Description |
| https://github.com/madler/zlib/issues/904 | Issue Tracking Exploit |
| https://github.com/madler/zlib/releases/tag/v1.3.2 | Release Notes |
| https://ostif.org/zlib-audit-complete/ | Product |
| https://7asecurity.com/reports/pentest-report-zlib-RC1.1.pdf | Technical Description |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-27171 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-27171
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
None
Dockerfile Python
Just-in-time kubectl exec access for Kubernetes. Request → Approve → Exec → Expire. No permanent permissions. Ever.
access-control devops fastapi helm jit kubectl kubernetes python rbac security pod role-based-access-control
Dockerfile Python Go Template Shell HTML
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-27171 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-27171 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Feb. 20, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Added CPE Configuration OR *cpe:2.3:a:zlib:zlib:*:*:*:*:*:*:*:* versions up to (excluding) 1.3.2 Added Reference Type MITRE: https://7asecurity.com/blog/2026/02/zlib-7asecurity-audit/ Types: Product Added Reference Type CISA-ADP: https://7asecurity.com/reports/pentest-report-zlib-RC1.1.pdf Types: Technical Description Added Reference Type MITRE: https://7asecurity.com/reports/pentest-report-zlib-RC1.1.pdf Types: Technical Description Added Reference Type MITRE: https://github.com/madler/zlib/issues/904 Types: Exploit, Issue Tracking Added Reference Type MITRE: https://github.com/madler/zlib/releases/tag/v1.3.2 Types: Release Notes Added Reference Type MITRE: https://ostif.org/zlib-audit-complete/ Types: Product -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Feb. 18, 2026
Action Type Old Value New Value Added Reference https://7asecurity.com/reports/pentest-report-zlib-RC1.1.pdf -
New CVE Received by [email protected]
Feb. 18, 2026
Action Type Old Value New Value Added 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. Added CVSS V3.1 AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L Added CWE CWE-1284 Added Reference https://7asecurity.com/blog/2026/02/zlib-7asecurity-audit/ Added Reference https://7asecurity.com/reports/pentest-report-zlib-RC1.1.pdf Added Reference https://github.com/madler/zlib/issues/904 Added Reference https://github.com/madler/zlib/releases/tag/v1.3.2 Added Reference https://ostif.org/zlib-audit-complete/