Use-after-free in Linux kernel - CVE-2026-31644

Vulnerability details

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to a use-after-free in lan966x_fdma_reload() when handling a failure to allocate new RX buffers during DMA reload. A local user can trigger the allocation failure and restart DMA with old descriptors whose pages were already freed to cause a denial of service.

The issue occurs on the restore path, where hardware may DMA into memory that has been returned to the buddy allocator and reused by other kernel subsystems.

Affected software

How to mitigate CVE-2026-31644

External References

• https://git.kernel.org/stable/c/59c3d55a946cacdb4181600723c20ac4f4c20c84
• https://git.kernel.org/stable/c/691082c0b93c13a5e068c0905f673060bddc204e
• https://git.kernel.org/stable/c/92a673019943770930e2a8bfd52e1aad47a1fc1f
• https://git.kernel.org/stable/c/9950e9199b3dfdfbde0b8d96ba947d7b11243801

Related Security Bulletins

• Use-after-free in Linux kernel microchip lan966x driver
• Debian update for linux