CVE-2026-63983

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

Description A packet loop occurs in the netem (Network Emulator) module when the duplicate feature is enabled. When netem duplicates a packet, it re-enqueues the copy at the root qdisc (Queueing Discipline). If another netem instance exists within the network tree, the copy may be duplicated repeatedly, leading to stack or memory exhaustion. The issue stems from the duplication guard relying on per-qdisc state q->duplicate, which is shared across concurrent enqueue paths and lacks sufficient locking. The fix involves using the tc depth field of the skb (socket buffer) to track duplication and skip the process if the value is already non-zero.

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