Cleartext transmission of sensitive information in Linux kernel - CVE-2021-45100
Published: December 16, 2021 / Updated: March 29, 2022
Vulnerability identifier: #VU92751
CSH Severity: Low
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2021-45100
CWE-ID: CWE-319
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote non-authenticated attacker to gain access to sensitive information.
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.
Affected software
Linux kernel
How to mitigate CVE-2021-45100
Install update from vendor's repository.