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.

The Unity Linux 20 host has a package installed that is affected by a vulnerability as referenced in the UTSA-2026-013424 advisory.

    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.

Tenable has extracted the preceding description block directly from the Unity Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The Unity Linux 20 host has a package installed that is affected by a vulnerability as referenced in the UTSA-2026-010738 advisory.

    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.

Tenable has extracted the preceding description block directly from the Unity Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - 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.
    (CVE-2021-45100)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Severity
309250	Unity Linux 20.1070a Security Update: kernel (UTSA-2026-013424)	Nessus	Unity Linux Local Security Checks	high
308425	Unity Linux 20.1070e Security Update: kernel (UTSA-2026-010738)	Nessus	Unity Linux Local Security Checks	high
250097	Linux Distros Unpatched Vulnerability : CVE-2021-45100	Nessus	Misc.	high

Detections

Analytics

CVE-2021-45100

high

Tenable Plugins

high

high

high