# CVE-2021-45100: linux: The ksmbd server through 3.4.2, as used in the Linux kernel through 5.15.8, sometimes communicates in cleartext even...

CVE-2021-45100 is fixed in linux on 1 platform, first by DEBIAN-CVE-2021-45100, released December 16, 2021. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2021-45100
- Priority: High
- CVSS: 7.5 (high)
- EPSS: 0.0091
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Dec 16, 2021

## Description

The ksmbd server through 3.4.2, as used in the Linux kernel through 5.15.8, sometimes communicates in cleartext even though encryption has been enabled. This occurs because it sets the SMB2_GLOBAL_CAP_ENCRYPTION flag when using the SMB 3.1.1 protocol, which is a violation of the SMB protocol specification. When Windows 10 detects this protocol violation, it disables encryption.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 5.15.15-1 | [DEBIAN-CVE-2021-45100](https://patchblox.com/security/data/fix/linux/debian-cve-2021-45100.md) | Dec 16, 2021 |
| Linux | linux Debian 13.5 (trixie) | 5.15.15-1 | [DEBIAN-CVE-2021-45100](https://patchblox.com/security/data/fix/linux/debian-cve-2021-45100.md) | Dec 16, 2021 |
| Linux | linux Debian 14 | 5.15.15-1 | [DEBIAN-CVE-2021-45100](https://patchblox.com/security/data/fix/linux/debian-cve-2021-45100.md) | Dec 16, 2021 |

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Data as of 2026-11-08T06:59:42Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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