CVE-2026-53079
MediumCVSS 5.5Exploitation Probability (EPSS)
Low risk1th percentile - higher than 1% of all known CVEs
Summary
A memory leak was found in the Linux kernel in the deferred packet drop mechanism of qdiscs. When the root qdisc does not implement the TCQ_F_DEQUEUE_DROPS flag, packets to be freed are not released and remain on a local list.
Risk Assessment
Memory leak can lead to exhaustion of system memory, potentially resulting in network performance degradation or system crash.
Recommendation
It is recommended to update the Linux kernel to a version containing the fix that makes qdisc_dequeue_drop() aware of the root qdisc and handles packets accordingly.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: net_sched: fix skb memory leak in deferred qdisc drops When the network stack cleans up the deferred list via qdisc_run_end(), it operates on the root qdisc. If the root qdisc do not implement the TCQ_F_DEQUEUE_DROPS flag the packets queue to free are never freed and gets stranded on the child's local to_free list. Fix this by making qdisc_dequeue_drop() aware of the root qdisc. It fetches the root qdisc and check for the TCQ_F_DEQUEUE_DROPS flag. If the flag is present, the packet is appended directly to the root's to_free list. Otherwise, drop it directly as it was done before the optimization was implemented.