CVE-2026-46322 tun: free page on build_skb failure in tun_xdp_one()
A memory leak in the Linux kernel's tun driver allows attackers to exhaust system memory via build_skb failures, causing denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-46322?
CVE-2026-46322 is a high-severity denial of service vulnerability in Linux kernel, published on 9 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
tun: free page on build_skb failure in tun_xdp_one()
When build_skb() fails in tun_xdp_one(), the function sets ret to -ENOMEM and jumps to the out label, which returns without freeing the page that vhost_net_build_xdp() allocated for the frame. As with the short-frame rejection path, tun_sendmsg() discards the per-buffer error and still returns total_len, so vhost_tx_batch() takes the success path and never frees the page. Each build_skb() failure in a batch leaks one page-frag chunk.
Free the page before taking the error path, matching the put_page() the other error exits of tun_xdp_one() already perform.
Weakness: CWE-401
Which versions are affected by CVE-2026-46322?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-46322?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-46322 being exploited?
There is no known exploitation of CVE-2026-46322 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-89678, BELL-CVE-2026-46322, DEBIAN-CVE-2026-46322, GHSA-3r6q-v9jg-jvv4, ROOT-OS-DEBIAN-11-CVE-2026-46322, ROOT-OS-DEBIAN-12-CVE-2026-46322 and 4 more.