CVE-2025-21643

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description The issue concerns the Linux kernel's handling of kernel-initiated asynchronous Direct I/O (DIO) operations. Specifically, the netfs extract user iter() function throws a warning and fails when handling async DIO writes because it only supports IOVEC and UBUF iterators. This can be triggered by a combination of cifs and a loopback blockdev. The problem causes a write to fail and generates a warning in the syslog. The estimated number of potentially affected devices worldwide is not available. There is no information about real-world incidents where this issue was exploited.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.