CVE-2026-52994 vsock/virtio: fix MSG_ZEROCOPY pinned-pages accounting
A flaw in Linux kernel vsock/virtio allows bypassing memory lock limits, potentially leading to resource exhaustion and denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-52994?
CVE-2026-52994 is a medium-severity denial of service vulnerability in Linux kernel, published on 24 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:
vsock/virtio: fix MSG_ZEROCOPY pinned-pages accounting
virtio_transport_init_zcopy_skb() uses iter->count as the size argument for msg_zerocopy_realloc(), which in turn passes it to mm_account_pinned_pages() for RLIMIT_MEMLOCK accounting. However, this function is called after virtio_transport_fill_skb() has already consumed the iterator via __zerocopy_sg_from_iter(), so on the last skb, iter->count will be 0, skipping the RLIMIT_MEMLOCK enforcement.
Pass pkt_len (the total bytes being sent) as an explicit parameter to virtio_transport_init_zcopy_skb() instead of reading the already-consumed iter->count.
This matches TCP and UDP, which both call msg_zerocopy_realloc() with the original message size.
Which versions are affected by CVE-2026-52994?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-52994?
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-2026-52994 being exploited?
There is no known exploitation of CVE-2026-52994 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-52994, DEBIAN-CVE-2026-52994, GHSA-c44p-q7r3-5852, ROOT-OS-DEBIAN-13-CVE-2026-52994, ROOT-OS-UBUNTU-2404-CVE-2026-52994, UBUNTU-CVE-2026-52994.