CVE-2026-46320 tap: free page on error paths in tap_get_user_xdp()
A memory leak in the Linux kernel's tap driver allows attackers to exhaust system memory by sending malformed frames, leading to 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-2026-46320?
CVE-2026-46320 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:
tap: free page on error paths in tap_get_user_xdp()
tap_get_user_xdp() rejects a frame shorter than ETH_HLEN with -EINVAL, and returns -ENOMEM when build_skb() fails. Both paths jump to the err label without freeing the page that vhost_net_build_xdp() allocated for the frame. tap_sendmsg() discards the per-buffer return value and always returns 0, so vhost_tx_batch() takes the success path and never frees the page; each rejected frame in a batch leaks one page-frag chunk.
Free the page on both error paths, before the skb is built. This is the tap counterpart of the same leak in tun_xdp_one().
Weakness: CWE-401
Which versions are affected by CVE-2026-46320?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-46320?
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-2026-46320 being exploited?
There is no known exploitation of CVE-2026-46320 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-89690, BELL-CVE-2026-46320, DEBIAN-CVE-2026-46320, GHSA-xqcf-gwj9-5c88, ROOT-OS-DEBIAN-11-CVE-2026-46320, ROOT-OS-DEBIAN-12-CVE-2026-46320 and 4 more.