CVE-2025-21971

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

Description A vulnerability in the Linux kernel has been identified, where the creation of classes with TC H ROOT can cause premature termination of the qdisc tree traversal. This leads to incorrect maintenance of parent statistics. In the case of DRR, it could result in a crash. The issue arises from the function qdisc tree reduce backlog() using TC H ROOT as a termination condition. To prevent this, the creation of any Qdisc class with classid TC H ROOT (0xFFFFFFFF) across all qdisc types is prevented.

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