{"id":"AZL-100226","summary":"CVE-2026-89483 affecting package kernel 6.6.150.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnvme: zero the discard fallback page\n\nnvme_setup_discard() always maps sizeof(struct nvme_dsm_range) *\nNVME_DSM_MAX_RANGES = 4096 bytes as the DSM payload however many ranges\nthe command declares, because some devices ignore the 'Number of Ranges'\nfield - the Fixes: commit records two that read past the declared ranges.\nA single-range discard fills only the first 16 bytes.\n\nNormally the buffer comes from kzalloc() and the other 4080 bytes are\nzero.  When that allocation fails the code falls back to the\nper-controller ctrl-\u003ediscard_page, which nvme_init_ctrl() obtains with\nalloc_page(GFP_KERNEL) and nothing ever zeroes, so those 4080 bytes are\nwhatever the page last held and are handed to the controller.  Reaching\nit requires the kzalloc(GFP_ATOMIC | __GFP_NOWARN) to fail, that is\nmemory pressure; it is not remotely triggerable.  Failing the allocation\nunder KMSAN reproduces it, with the leaked tail full of vmemmap struct\npage pointers.  The extent in the report is a partial transfer of the\npayload, not the whole 4096 bytes; the 16-byte boundary in it is the one\ndeclared range:\n\n[   11.991601] BUG: KMSAN: uninit-value in dma_map_phys+0x14c8/0x1900\n[   11.991969]  dma_map_phys+0x14c8/0x1900\n[   11.992220]  dma_map_page_attrs+0xcf/0x130\n[   11.992485]  e1000_xmit_frame+0x4099/0x6d10\n[   11.992768]  dev_hard_start_xmit+0x22f/0xa80\n[   11.993068]  sch_direct_xmit+0x35c/0xcb0\n[   11.993315]  __dev_queue_xmit+0x1ee5/0x5eb0\n[   11.993608]  ip_finish_output2+0x1903/0x1c30\n[   11.993881]  ip_finish_output+0x288/0x870\n[   11.994125]  ip_output+0x15e/0x400\n[   11.994365]  __ip_queue_xmit+0x1e85/0x1fb0\n[   11.994639]  ip_queue_xmit+0x60/0x80\n[   11.994899]  __tcp_transmit_skb+0x4e71/0x5fa0\n[   11.995210]  tcp_write_xmit+0x3a36/0x9160\n[   11.995533]  __tcp_push_pending_frames+0xc5/0x3c0\n[   11.995854]  tcp_push+0x7dc/0x840\n[   11.996076]  tcp_sendmsg_locked+0x766c/0x8400\n[   11.996371]  tcp_sendmsg+0x4b/0x90\n[   11.996572]  inet_sendmsg+0x134/0x2a0\n[   11.996823]  __sock_sendmsg+0x265/0x360\n[   11.997076]  sock_sendmsg+0x100/0x1e0\n[   11.997293]  nvme_tcp_try_send+0x196f/0x6370\n[   11.997605]  nvme_tcp_queue_rq+0x1d54/0x20b0\n[   11.997882]  blk_mq_dispatch_rq_list+0x5ee/0x2e50\n[   11.998175]  __blk_mq_sched_dispatch_requests+0x16dc/0x24a0\n[   11.998539]  blk_mq_sched_dispatch_requests+0x11b/0x2c0\n[   11.998865]  blk_mq_run_work_fn+0x13b/0x280\n[   11.999146]  process_scheduled_works+0x966/0x1ad0\n[   11.999465]  worker_thread+0xe44/0x1480\n[   11.999709]  kthread+0x53b/0x600\n[   11.999927]  ret_from_fork+0x29f/0x7c0\n[   12.000191]  ret_from_fork_asm+0x1a/0x30\n[   12.000460]\n[   12.000558] Uninit was created at:\n[   12.000788]  __alloc_frozen_pages_noprof+0x8bf/0xd30\n[   12.001096]  alloc_pages_mpol+0x1d0/0x5f0\n[   12.001326]  alloc_pages_noprof+0x102/0x290\n[   12.001627]  nvme_init_ctrl+0x5a3/0x9f0\n[   12.001891]  nvme_tcp_create_ctrl+0xd75/0x19b0\n[   12.002170]  nvmf_dev_write+0x4c68/0x4fd0\n[   12.002426]  vfs_write+0x587/0x1a10\n[   12.002636]  __x64_sys_write+0x207/0x4f0\n[   12.002874]  x64_sys_call+0x2ff0/0x3ea0\n[   12.003123]  do_syscall_64+0x147/0x3b0\n[   12.003400]  entry_SYSCALL_64_after_hwframe+0x77/0x7f\n[   12.003680]\n[   12.003777] Bytes 16-2843 of 2844 are uninitialized\n[   12.004068] Memory access of size 2844 starts at ffff888109f82000\n[   12.004412]\n[   12.004530] CPU: 0 UID: 0 PID: 101 Comm: kworker/0:1H Not tainted 7.2.0-rc5-NVMECTL-gf5098b6bae76 #1 PREEMPT(lazy)\n[   12.005127] Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\n[   12.005762] Workqueue: kblockd blk_mq_run_work_fn\n[   12.006073] =====================================================\n\nAllocate the page with __GFP_ZERO.  The single allocation site covers\nevery use of it: bytes no discard has written stay zero, and bytes one\ndid write hold that controller's own range list, which it has already\nbeen sent.","modified":"2026-09-13T06:06:36Z","published":"2026-09-11T20:19:29Z","upstream":["CVE-2026-89483"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89483"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"6.6.150.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-100226.json"}}],"schema_version":"1.9.0"}