Vulnerability · Published Feb 18, 2026 · Assigned by mitre
CVE-2026-27171
Low 2.9
In plain English
A low-severity security flaw in zlib from zlib. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 16% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)2.9Low
Exploit odds (30 days)0.2%top 83.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | zlib | 1.3.2-r0 | ALPINE-CVE-2026-27171 |
| Alpine:v3.21 | zlib | 1.3.2-r0 | ALPINE-CVE-2026-27171 |
| Alpine:v3.22 | zlib | 1.3.2-r0 | ALPINE-CVE-2026-27171 |
| Alpine:v3.23 | zlib | 1.3.2-r0 | ALPINE-CVE-2026-27171 |
| Alpine:v3.24 | zlib | 1.3.2-r0 | ALPINE-CVE-2026-27171 |
| Debian:12 | zlib | no fix listed | DEBIAN-CVE-2026-27171 |
| Debian:13 | zlib | no fix listed | DEBIAN-CVE-2026-27171 |
| Debian:14 | zlib | 1:1.3.dfsg+really1.3.2-1 | DEBIAN-CVE-2026-27171 |
| Ubuntu:24.04:LTS | zlib | 1:1.3.dfsg-3.1ubuntu2.2 | USN-8706-1 |
| Ubuntu:24.04:LTS | zlib | 1:1.3.dfsg-3.1ubuntu2.2 | UBUNTU-CVE-2026-27171 |
| Ubuntu:25.10 | zlib | no fix listed | UBUNTU-CVE-2026-27171 |
| Ubuntu:26.04:LTS | zlib | 1:1.3.dfsg+really1.3.1-1ubuntu3.1 | UBUNTU-CVE-2026-27171 |
| Ubuntu:26.04:LTS | zlib | 1:1.3.dfsg+really1.3.1-1ubuntu3.1 | USN-8706-1 |
Affected products (as reported)
Weakness: CWE-1284 · Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L