The Linux kernel contains a use‑after‑free vulnerability involving VXLAN multicast domain backend (MDB) entry deletion. When a source list that includes an all‑zeros address is removed, the code deletes a forwarding entry, frees the source entry, and then tries to delete the freed entry, causing a kernel memory corruption that is exposed as a KASAN slab-use-after-free failure. An attacker could trigger this fault by creating or modifying VXLAN MDB entries with an all‑zeros source address from a new user or network namespace, potentially leading to a crash or looser kernel state. The flaw does not require elevated privileges beyond the ability to manipulate VXLAN MDB entries, which a local user can perform in a private namespace.

All Linux kernel releases that implement VXLAN MDB functionality and are affected by this unpatched use‑after‑free bug. The specific affected versions are not listed, so any kernel prior to the confirmed fix commit is at risk. Users operating a Linux system that relies on VXLAN operations, especially in isolated user or network namespaces, should consider the vulnerability to be present until they upgrade the kernel.

The vulnerability inherits the characteristics of a kernel use‑after‑free, which is normally high severity due to the potential for a system crash or privileged escalation. No EPSS score is published, and the issue is not catalogued in CISA's KEV list, suggesting that publicly known exploitation may not have been observed yet. However, attackers can locally trigger the fault from a standard user context that creates or deletes VXLAN MDB entries, making the attack vector local and feasible for an attacker with physical or remote console access. Given the lack of a publicly available exploit and the absence of a KEV listing, the risk can be considered serious but not yet proven in the wild.