CVE-2026-31644 net: lan966x: fix use-after-free and leak in lan966x_fdma_reload()
A use-after-free in the lan966x network driver allows attackers to cause memory corruption or denial of service via DMA operations.
- 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-2026-31644?
CVE-2026-31644 is a high-severity use after free vulnerability in Linux kernel, published on 24 Apr 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:
net: lan966x: fix use-after-free and leak in lan966x_fdma_reload()
When lan966x_fdma_reload() fails to allocate new RX buffers, the restore path restarts DMA using old descriptors whose pages were already freed via lan966x_fdma_rx_free_pages(). Since page_pool_put_full_page() can release pages back to the buddy allocator, the hardware may DMA into memory now owned by other kernel subsystems.
Additionally, on the restore path, the newly created page pool (if allocation partially succeeded) is overwritten without being destroyed, leaking it.
Fix both issues by deferring the release of old pages until after the new allocation succeeds. Save the old page array before the allocation so old pages can be freed on the success path. On the failure path, the old descriptors, pages and page pool are all still valid, making the restore safe. Also ensure the restore path re-enables NAPI and wakes the netdev, matching the success path.
Weakness: CWE-416
Which versions are affected by CVE-2026-31644?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-31644?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-31644 being exploited?
There is no known exploitation of CVE-2026-31644 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-31644, DEBIAN-CVE-2026-31644, GHSA-24xp-grcx-7gv9, UBUNTU-CVE-2026-31644.