CVE-2025-21922

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

Description A vulnerability has been resolved in the Linux kernel related to the ppp driver, which fails to initialize a 2-byte header when using socket filter, causing a KMSAN uninit-value warning. This issue can be triggered by carefully crafted BPF programs, such as those generated by syzkaller, which start reading from offset 0. The vulnerable code skips 2 bytes of data and then reads the Protocol field to determine if it's an IP packet, and then reads the first byte of the first 2 bytes to determine the direction. However, only the first byte indicating direction is initialized in the current ppp driver code, while the second byte is not initialized.

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