# 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.

CVE-2026-27171 is fixed in 37 products on 1 platform, first by lib32z1 1:1.3.dfsg-3.1ubuntu2.2, released February 17, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-27171
- Priority: Routine
- CVSS: 5.5 (Low)
- EPSS: 0.0025
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Feb 17, 2026
- Weakness: Improper Validation of Specified Quantity in Input
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-27171

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | lib32z1 Ubuntu 24.04.5 LTS (noble) | 1:1.3.dfsg-3.1ubuntu2.2 | [lib32z1 1:1.3.dfsg-3.1ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-noble-lib32z1-1-1.3.dfsg-3.1ubuntu2.2.md) | Feb 17, 2026 |
| Linux | lib32z1 Ubuntu 26.04.1 LTS (resolute) | 1:1.3.dfsg+really1.3.1-1ubuntu3.1 | [lib32z1 1:1.3.dfsg+really1.3.1-1ubuntu3.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-lib32z1-1-1.3.dfsg-really1.3.1-1ubuntu3.1.md) | Feb 17, 2026 |
| Linux | lib64z1 Ubuntu 24.04.5 LTS (noble) | 1:1.3.dfsg-3.1ubuntu2.2 | [lib64z1 1:1.3.dfsg-3.1ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-noble-lib64z1-1-1.3.dfsg-3.1ubuntu2.2.md) | Feb 17, 2026 |
| Linux | lib64z1 Ubuntu 26.04.1 LTS (resolute) | 1:1.3.dfsg+really1.3.1-1ubuntu3.1 | [lib64z1 1:1.3.dfsg+really1.3.1-1ubuntu3.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-lib64z1-1-1.3.dfsg-really1.3.1-1ubuntu3.1.md) | Feb 17, 2026 |
| Linux | libminizip1t64 Ubuntu 24.04.5 LTS (noble) | 1:1.3.dfsg-3.1ubuntu2.2 | [libminizip1t64 1:1.3.dfsg-3.1ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libminizip1t64-1-1.3.dfsg-3.1ubuntu2.2.md) | Feb 17, 2026 |
| Linux | libminizip1t64 Ubuntu 26.04.1 LTS (resolute) | 1:1.3.dfsg+really1.3.1-1ubuntu3.1 | [libminizip1t64 1:1.3.dfsg+really1.3.1-1ubuntu3.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libminizip1t64-1-1.3.dfsg-really1.3.1-1ubuntu3.1.md) | Feb 17, 2026 |
| Linux | libx32z1 Ubuntu 24.04.5 LTS (noble) | 1:1.3.dfsg-3.1ubuntu2.2 | [libx32z1 1:1.3.dfsg-3.1ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libx32z1-1-1.3.dfsg-3.1ubuntu2.2.md) | Feb 17, 2026 |
| Linux | libx32z1 Ubuntu 26.04.1 LTS (resolute) | 1:1.3.dfsg+really1.3.1-1ubuntu3.1 | [libx32z1 1:1.3.dfsg+really1.3.1-1ubuntu3.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libx32z1-1-1.3.dfsg-really1.3.1-1ubuntu3.1.md) | Feb 17, 2026 |
| Linux | minizip Ubuntu 24.04.5 LTS (noble) | 1:1.3.dfsg-3.1ubuntu2.2 | [minizip 1:1.3.dfsg-3.1ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-noble-minizip-1-1.3.dfsg-3.1ubuntu2.2.md) | Feb 17, 2026 |
| Linux | minizip Ubuntu 26.04.1 LTS (resolute) | 1:1.3.dfsg+really1.3.1-1ubuntu3.1 | [minizip 1:1.3.dfsg+really1.3.1-1ubuntu3.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-minizip-1-1.3.dfsg-really1.3.1-1ubuntu3.1.md) | Feb 17, 2026 |
| Linux | nodejs20 amzn 2023 | 1:20.20.2-1.amzn2023.0.2 | [ALAS2023-2026-1608](https://patchblox.com/security/data/fix/linux/alas2023-2026-1608.md) | Apr 27, 2026 |
| Linux | nodejs20-debuginfo amzn 2023 | 1:20.20.2-1.amzn2023.0.2 | [ALAS2023-2026-1608](https://patchblox.com/security/data/fix/linux/alas2023-2026-1608.md) | Apr 27, 2026 |
| Linux | nodejs20-debugsource amzn 2023 | 1:20.20.2-1.amzn2023.0.2 | [ALAS2023-2026-1608](https://patchblox.com/security/data/fix/linux/alas2023-2026-1608.md) | Apr 27, 2026 |
| Linux | nodejs20-devel amzn 2023 | 1:20.20.2-1.amzn2023.0.2 | [ALAS2023-2026-1608](https://patchblox.com/security/data/fix/linux/alas2023-2026-1608.md) | Apr 27, 2026 |
| Linux | nodejs20-docs amzn 2023 | 1:20.20.2-1.amzn2023.0.2 | [ALAS2023-2026-1608](https://patchblox.com/security/data/fix/linux/alas2023-2026-1608.md) | Apr 27, 2026 |
| Linux | nodejs20-full-i18n amzn 2023 | 1:20.20.2-1.amzn2023.0.2 | [ALAS2023-2026-1608](https://patchblox.com/security/data/fix/linux/alas2023-2026-1608.md) | Apr 27, 2026 |
| Linux | nodejs20-libs amzn 2023 | 1:20.20.2-1.amzn2023.0.2 | [ALAS2023-2026-1608](https://patchblox.com/security/data/fix/linux/alas2023-2026-1608.md) | Apr 27, 2026 |
| Linux | nodejs20-libs-debuginfo amzn 2023 | 1:20.20.2-1.amzn2023.0.2 | [ALAS2023-2026-1608](https://patchblox.com/security/data/fix/linux/alas2023-2026-1608.md) | Apr 27, 2026 |
| Linux | nodejs20-npm amzn 2023 | 1:10.8.2-1.20.20.2.1.amzn2023.0.2 | [ALAS2023-2026-1608](https://patchblox.com/security/data/fix/linux/alas2023-2026-1608.md) | Apr 27, 2026 |
| Linux | nodejs22 amzn 2023 | 1:22.22.2-1.amzn2023.0.2 | [ALAS2023-2026-1616](https://patchblox.com/security/data/fix/linux/alas2023-2026-1616.md) | Apr 27, 2026 |
| Linux | nodejs22-debuginfo amzn 2023 | 1:22.22.2-1.amzn2023.0.2 | [ALAS2023-2026-1616](https://patchblox.com/security/data/fix/linux/alas2023-2026-1616.md) | Apr 27, 2026 |
| Linux | nodejs22-debugsource amzn 2023 | 1:22.22.2-1.amzn2023.0.2 | [ALAS2023-2026-1616](https://patchblox.com/security/data/fix/linux/alas2023-2026-1616.md) | Apr 27, 2026 |
| Linux | nodejs22-devel amzn 2023 | 1:22.22.2-1.amzn2023.0.2 | [ALAS2023-2026-1616](https://patchblox.com/security/data/fix/linux/alas2023-2026-1616.md) | Apr 27, 2026 |
| Linux | nodejs22-docs amzn 2023 | 1:22.22.2-1.amzn2023.0.2 | [ALAS2023-2026-1616](https://patchblox.com/security/data/fix/linux/alas2023-2026-1616.md) | Apr 27, 2026 |
| Linux | nodejs22-full-i18n amzn 2023 | 1:22.22.2-1.amzn2023.0.2 | [ALAS2023-2026-1616](https://patchblox.com/security/data/fix/linux/alas2023-2026-1616.md) | Apr 27, 2026 |
| Linux | nodejs22-libs amzn 2023 | 1:22.22.2-1.amzn2023.0.2 | [ALAS2023-2026-1616](https://patchblox.com/security/data/fix/linux/alas2023-2026-1616.md) | Apr 27, 2026 |
| Linux | nodejs22-libs-debuginfo amzn 2023 | 1:22.22.2-1.amzn2023.0.2 | [ALAS2023-2026-1616](https://patchblox.com/security/data/fix/linux/alas2023-2026-1616.md) | Apr 27, 2026 |
| Linux | nodejs22-npm amzn 2023 | 1:10.9.7-1.22.22.2.1.amzn2023.0.2 | [ALAS2023-2026-1616](https://patchblox.com/security/data/fix/linux/alas2023-2026-1616.md) | Apr 27, 2026 |
| Linux | nodejs24 amzn 2023 | 1:24.15.0-1.amzn2023.0.1 | [ALAS2023-2026-1609](https://patchblox.com/security/data/fix/linux/alas2023-2026-1609.md) | Apr 27, 2026 |
| Linux | nodejs24-debuginfo amzn 2023 | 1:24.15.0-1.amzn2023.0.1 | [ALAS2023-2026-1609](https://patchblox.com/security/data/fix/linux/alas2023-2026-1609.md) | Apr 27, 2026 |
| Linux | nodejs24-debugsource amzn 2023 | 1:24.15.0-1.amzn2023.0.1 | [ALAS2023-2026-1609](https://patchblox.com/security/data/fix/linux/alas2023-2026-1609.md) | Apr 27, 2026 |
| Linux | nodejs24-devel amzn 2023 | 1:24.15.0-1.amzn2023.0.1 | [ALAS2023-2026-1609](https://patchblox.com/security/data/fix/linux/alas2023-2026-1609.md) | Apr 27, 2026 |
| Linux | nodejs24-docs amzn 2023 | 1:24.15.0-1.amzn2023.0.1 | [ALAS2023-2026-1609](https://patchblox.com/security/data/fix/linux/alas2023-2026-1609.md) | Apr 27, 2026 |
| Linux | nodejs24-full-i18n amzn 2023 | 1:24.15.0-1.amzn2023.0.1 | [ALAS2023-2026-1609](https://patchblox.com/security/data/fix/linux/alas2023-2026-1609.md) | Apr 27, 2026 |
| Linux | nodejs24-libs amzn 2023 | 1:24.15.0-1.amzn2023.0.1 | [ALAS2023-2026-1609](https://patchblox.com/security/data/fix/linux/alas2023-2026-1609.md) | Apr 27, 2026 |
| Linux | nodejs24-libs-debuginfo amzn 2023 | 1:24.15.0-1.amzn2023.0.1 | [ALAS2023-2026-1609](https://patchblox.com/security/data/fix/linux/alas2023-2026-1609.md) | Apr 27, 2026 |
| Linux | nodejs24-npm amzn 2023 | 1:11.12.1-1.24.15.0.1.amzn2023.0.1 | [ALAS2023-2026-1609](https://patchblox.com/security/data/fix/linux/alas2023-2026-1609.md) | Apr 27, 2026 |
| Linux | v8-11.3-devel amzn 2023 | 3:11.3.244.8-1.20.20.2.1.amzn2023.0.2 | [ALAS2023-2026-1608](https://patchblox.com/security/data/fix/linux/alas2023-2026-1608.md) | Apr 27, 2026 |
| Linux | v8-12.4-devel amzn 2023 | 3:12.4.254.21-1.22.22.2.1.amzn2023.0.2 | [ALAS2023-2026-1616](https://patchblox.com/security/data/fix/linux/alas2023-2026-1616.md) | Apr 27, 2026 |
| Linux | v8-13.6-devel amzn 2023 | 3:13.6.233.17-1.24.15.0.1.amzn2023.0.1 | [ALAS2023-2026-1609](https://patchblox.com/security/data/fix/linux/alas2023-2026-1609.md) | Apr 27, 2026 |
| Linux | zlib Debian 13.5 (trixie) | 1:1.3.dfsg+really1.3.1-1+deb13u1 | [DEBIAN-CVE-2026-27171](https://patchblox.com/security/data/fix/linux/debian-cve-2026-27171.md) | Feb 18, 2026 |
| Linux | zlib Debian 14 | 1:1.3.dfsg+really1.3.2-1 | [DEBIAN-CVE-2026-27171](https://patchblox.com/security/data/fix/linux/debian-cve-2026-27171.md) | Feb 18, 2026 |
| Linux | zlib opensuse-leap 15.6 | 1.2.13-150500.4.6.1 | [SUSE-SU-2026:0783-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-0783-1.md) | Mar 3, 2026 |
| Linux | zlib opensuse-leap 16.0 | 1.2.13-160000.3.1 | [OPENSUSE-SU-2026:20487-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-20487-1.md) | Apr 9, 2026 |
| Linux | zlib sles 15.7 | 1.2.13-150500.4.6.1 | [SUSE-SU-2026:0783-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-0783-1.md) | Mar 3, 2026 |
| Linux | zlib sles 16.0 | 1.2.13-160000.3.1 | [SUSE-SU-2026:21151-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-21151-1.md) | Apr 9, 2026 |
| Linux | zlib1g Ubuntu 24.04.5 LTS (noble) | 1:1.3.dfsg-3.1ubuntu2.2 | [zlib1g 1:1.3.dfsg-3.1ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-noble-zlib1g-1-1.3.dfsg-3.1ubuntu2.2.md) | Feb 17, 2026 |
| Linux | zlib1g Ubuntu 26.04.1 LTS (resolute) | 1:1.3.dfsg+really1.3.1-1ubuntu3.1 | [zlib1g 1:1.3.dfsg+really1.3.1-1ubuntu3.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-zlib1g-1-1.3.dfsg-really1.3.1-1ubuntu3.1.md) | Feb 17, 2026 |

---

Data as of 2026-11-09T01:18:40Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data

Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.