CVE-2026-80788

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CVE-2026-80788

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

Details: 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.

References: https://git.kernel.org/stable/c/737a3b535247226f6e1a7988fd9d6e63e7d6fc71, https://git.kernel.org/stable/c/7b6a54d4e7b0da423c2b53ed293fd36b16c0b19e, https://git.kernel.org/stable/c/7fd6da0f28932442b51658bac4ff55565ca9b377, https://git.kernel.org/stable/c/86cc450022473c4a29b43a09f3ec22a9ef566dac, https://git.kernel.org/stable/c/8d01f0d0e96485e39ad89b859ef85e1dc3020465, https://git.kernel.org/stable/c/9b770e40bc00381e5ebf53653de5776773415be3, https://git.kernel.org/stable/c/9c95f7e66c62ee6c6abedcf1c04311f430ff5833, https://git.kernel.org/stable/c/c509f20be1cabda3087810bb2d658d66b3f31f35, https://git.kernel.org/stable/c/e7077e6c45423dd2bb7de7b5fc4b018a8e6c4741, https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80788.json, https://nvd.nist.gov/vuln/detail/CVE-2026-80788, https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git