CVE-2026-80788

About vulnerability

In the Linux kernel, the following vulnerability has been resolved:

nvmet-tcp: Do not WARN on remotely-controlled oversized SGL allocations

When fuzzing the nvme target code, I tripped a kernel warning in nvmet_tcp_map_data() because the length passed into the allocator is controlled by the remote initiator.

A remote initiator that sends a command with an SGL claiming a huge number, can create a scatterlist and iovec allocation of over 1 million entries, which causes the backing kmalloc call to exceed MAX_PAGE_ORDER and then the page allocator will trip on a WARN_ON_ONCE_GFP() message:

WARNING: mm/page_alloc.c:5280 __alloc_frozen_pages_noprof Workqueue: nvmet_tcp_wq nvmet_tcp_io_work … sgl_alloc_order nvmet_tcp_map_data nvmet_tcp_try_recv_pdu

As it’s never good to trip a kernel warning remotely due to many systems having panic-on-warn enabled, let’s silence it by just add GFP_NOWARN to the allocation flags.

Affected product:

AlmaLinux 9.2 ESU , Amazon Linux 2 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , Debian 11 ELS , Oracle Linux 7 ELS , TuxCare 9.6 ESU , TuxCare 9.8 ESU , Ubuntu 20.04 ELS

Affected packages:

linux @ 5.4.0 (+9 more)

Live-patch status from KernelCare for each operating system.