CVE-2025-21971

In the Linux kernel, the following vulnerability has been resolved: net_sched: Prevent creation of classes with TC_H_ROOT The function qdisc_tree_reduce_backlog() uses TC_H_ROOT as a termination condition when traversing up the qdisc tree to update parent backlog counters. However, if a class is created with classid TC_H_ROOT, the traversal terminates prematurely at this class instead of reaching the actual root qdisc, causing parent statistics to be incorrectly maintained. In case of DRR, this could lead to a crash as reported by Mingi Cho. Prevent the creation of any Qdisc class with classid TC_H_ROOT (0xFFFFFFFF) across all qdisc types, as suggested by Jamal.

Chenyuan Yang discovered that the CEC driver driver in the Linux kernel contained a use-after-free vulnerability. A local attacker could use this to cause a denial of service or possibly execute arbitrary code. Attila Sz�sz discovered that the HFS+ file system implementation in the Linux Kernel contained a heap overflow vulnerability. An attacker could use a specially crafted file system image that, when mounted, could cause a denial of service or possibly execute arbitrary code.