Linux · Linux Kernel · CVE-2025-38553
Name of the Vulnerable Software and Affected Versions:
Linux kernel (affected versions not specified)
Description:
A flaw exists in the Linux kernel's net/sched subsystem related to the handling of netem (network emulator) queuing disciplines (qdiscs). The duplication prevention logic within `netem enqueue` fails when a netem instance resides within a qdisc tree alongside other netem instances. This can lead to a soft lockup and an out-of-memory (OOM) loop during `netem dequeue`. The issue arises from the potential for duplicated netem instances to exist within the same qdisc tree. Previous attempts to address this included tracking duplication status in the `sk buff` structure, restricting recursion depth, and using metadata in `netem skb cb`, but these were deemed either too specific, bypassable, or overly complex. The current solution prevents a duplicating netem from existing in the same tree as other netems.
Recommendations:
At the moment, there is no information about a newer version that contains a fix for this vulnerability.