CVE-2026-46321
HighCVSS 7.1Exploitation Probability (EPSS)
Low risk3th percentile - higher than 3% of all known CVEs
Summary
In the Linux kernel, a memory leak was found in tun_xdp_one() when rejecting short frames. If a frame is shorter than ETH_HLEN, the function returns -EINVAL but does not free the page allocated by vhost_net_build_xdp(). This causes a page-frag leak for each rejected frame.
Risk Assessment
A local user with access to /dev/net/tun and /dev/vhost-net can intentionally send short frames, exhausting host memory and causing an OOM panic. This poses a denial-of-service risk.
Recommendation
Apply the Linux kernel patch that frees the page before returning -EINVAL in tun_xdp_one(). Update to a kernel version containing this fix as soon as possible.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: tun: free page on short-frame rejection in tun_xdp_one() tun_xdp_one() returns -EINVAL on a frame shorter than ETH_HLEN without freeing the page that vhost_net_build_xdp() allocated for it. tun_sendmsg() discards that -EINVAL and still returns total_len, so vhost_tx_batch() takes the success path and never frees the page; each short frame in a batch leaks one page-frag chunk. A local process that can open /dev/net/tun and /dev/vhost-net can hit this path: it attaches a tun/tap device as the vhost-net backend and feeds TX descriptors whose length minus the virtio-net header is below ETH_HLEN. Each kick leaks the page-frag chunks for that batch, and a tight submission loop exhausts host memory and triggers an OOM panic. Free the page before returning -EINVAL, matching the XDP-program error path in the same function.