# CVE-2026-90173: linux: In the Linux kernel, the following vulnerability has been resolved: smb: smbdirect: free completion queues with ib_f... CVE-2026-90173 is fixed in linux on 1 platform by DEBIAN-CVE-2026-90173 (version 7.2.6-1), released September 23, 2026. It is not reported as exploited. Patch Radar priority: Urgent. - Web page: https://patchblox.com/security/cve/CVE-2026-90173 - Priority: Urgent - CVSS: 9.8 (critical) - EPSS: 0.0055 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Sep 17, 2026 ## Description In the Linux kernel, the following vulnerability has been resolved: smb: smbdirect: free completion queues with ib_free_cq() smbdirect_connection_destroy_qp() creates the send and receive completion queues with ib_alloc_cq_any(), which for IB_POLL_WORKQUEUE arms an internal completion handler that runs ib_cq_poll_work() on a workqueue. Tearing those CQs down with ib_destroy_cq() frees them without first cancelling that poll work. If the provider posts a completion late -- for example Soft-RoCE (rxe) posting an RNR error from rxe_receiver() after rdma_destroy_qp() -- the handler re-queues ib_cq_poll_work() on the already-freed CQ, and a follow-on access faults in rxe_req_notify_cq(). Use ib_free_cq(), which cancel_work_sync()es the poll work before freeing the CQ, so no completion handler can run against a freed queue. [ 1236.599526] ================================================================== [ 1236.602142] BUG: KASAN: slab-use-after-free in ib_cq_poll_work+0xd0/0x1a0 [ 1236.605524] Read of size 8 at addr ffff888111865800 by task kworker/4:1H/82 [ 1236.609017] [ 1236.609270] CPU: 4 UID: 0 PID: 82 Comm: kworker/4:1H Not tainted 7.2.0-rc3-next-20260717-virtme #110 PREEMPT(lazy) [ 1236.609287] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-debian-1.17.0-1 04/01/2014 [ 1236.609498] Workqueue: ib-comp-wq ib_cq_poll_work [ 1236.609525] Call Trace: [ 1236.609536] [ 1236.609545] __dump_stack+0x21/0x60 [ 1236.609562] dump_stack_lvl+0xc2/0x100 [ 1236.609573] print_address_description+0x77/0x200 [ 1236.609587] ? ib_cq_poll_work+0xd0/0x1a0 [ 1236.609597] print_report+0x58/0x70 [ 1236.609607] kasan_report+0x117/0x150 [ 1236.609623] ? ib_cq_poll_work+0xd0/0x1a0 [ 1236.609636] ? process_scheduled_works+0x954/0x1600 [ 1236.609650] ib_cq_poll_work+0xd0/0x1a0 [ 1236.609662] ? process_scheduled_works+0x954/0x1600 [ 1236.609674] process_scheduled_works+0xc22/0x1600 [ 1236.609698] ? __pfx_process_scheduled_works+0x10/0x10 [ 1236.609713] ? __pfx_assign_work+0x10/0x10 [ 1236.609726] ? lock_is_held_type+0x7b/0x110 [ 1236.609741] worker_thread+0x975/0xee0 [ 1236.609757] ? __pfx_do_raw_spin_lock+0x10/0x10 [ 1236.609775] ? __kthread_parkme+0x21e/0x260 [ 1236.609789] kthread+0x3a6/0x490 [ 1236.609800] ? __pfx_worker_thread+0x10/0x10 [ 1236.609809] ? __pfx_kthread+0x10/0x10 [ 1236.609820] ret_from_fork+0x55a/0xa20 [ 1236.609835] ? __pfx_ret_from_fork+0x10/0x10 [ 1236.609850] ? __pfx_kthread+0x10/0x10 [ 1236.609861] ret_from_fork_asm+0x1a/0x30 [ 1236.609880] [ 1236.609886] [ 1236.661292] Allocated by task 5076: [ 1236.662640] kasan_save_track+0x3e/0x80 [ 1236.663842] __kasan_kmalloc+0x72/0x90 [ 1236.664763] __kmalloc_noprof+0x2b0/0x5d0 [ 1236.665356] __ib_alloc_cq+0x284/0x1000 [ 1236.666573] __ib_alloc_cq_any+0x23e/0x340 [ 1236.668654] smbdirect_connection_create_qp+0x6f7/0x1070 [ 1236.669757] smbdirect_accept_connect_request+0x500/0x1ca0 [ 1236.672625] smbdirect_listen_rdma_event_handler+0x1655/0x1c50 [ 1236.673930] cma_listen_handler+0x1bf/0x260 [ 1236.674923] cma_cm_event_handler+0x128/0x380 [ 1236.676926] cma_ib_req_handler+0x2d3d/0x4de0 [ 1236.678368] cm_process_work+0xb0/0x530 [ 1236.680454] cm_queue_work_unlock+0xb1/0x230 [ 1236.681673] cm_work_handler+0x969f/0xdca0 [ 1236.682704] process_scheduled_works+0xc22/0x1600 [ 1236.683447] worker_thread+0x975/0xee0 [ 1236.685901] kthread+0x3a6/0x490 [ 1236.688164] ret_from_fork+0x55a/0xa20 [ 1236.689522] ret_from_fork_asm+0x1a/0x30 [ 1236.690073] [ 1236.690378] Freed by task 5137: [ 1236.692242] kasan_save_track+0x3e/0x80 [ 1236.694272] kasan_save_free_info+0x40/0x50 [ 1236.695514] __kasan_slab_free+0x3a/0x60 [ 1236.696773] kfree+0x14e/0x4e0 [ 1236.697216] ib_destroy_cq_user+0x18d/0x250 [ 1236.699817] smbdirect_connection_destroy_qp+0xf2/0x280 [ 1236.702115] smbdirect_socket_destroy_sync+0x1607/0x2720 [ 1236.704062] smbdirect_socket_release+0x140/0x280 [ 1236.705286] smb_direct_free_transpor ---truncated--- ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | linux Debian 14 | 7.2.6-1 | [DEBIAN-CVE-2026-90173](https://patchblox.com/security/data/fix/linux/debian-cve-2026-90173.md) | Sep 23, 2026 | --- Data as of 2026-11-08T06:59:42Z UTC. 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