Executive brief
A memory leak vulnerability was identified in the Linux kernel's network scheduling component. This issue occurs when the system fails to properly release memory used for network packets during certain traffic management operations. Over time, this could lead to system instability or performance degradation as available memory is exhausted.
Technical details
A memory leak exists in the Linux kernel's net_sched subsystem within the qdisc_dequeue_drop() function. When the network stack cleans up the deferred list via qdisc_run_end(), it operates on the root qdisc; however, if the root qdisc does not implement the TCQ_F_DEQUEUE_DROPS flag, packets queued for deletion are never freed and remain stranded on the child's local to_free list. This vulnerability is triggered during specific network traffic shaping conditions. The fix involves making qdisc_dequeue_drop() aware of the root qdisc and ensuring packets are either appended to the root's to_free list or dropped immediately if the flag is absent. Patches have been released in various stable kernel branches.
Affected products
- Linux Linux Kernel 6.19, 7.0.10, 7.1
Timeline
- 2026-04-08: other: Patch authored
- 2026-06-24: disclosed: CVE published