CVE-2026-90173

CRITICAL CVSS 9.8 PoC Available

Published: 2026-09-17

Modified: 2026-09-18

Enriched via mock

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AI Threat Summary

CVE-2026-90173 is a critical vulnerability with a CVSS score of 9.8 affecting the target software. Threat hunters should monitor for exploit attempts and apply vendor patches immediately.

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] <TASK> [ 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] </TASK> [ 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---

Attack Chain

Reconnaissance

Attacker scans for vulnerable versions using version banners or PoC scanners

Initial Access

Attacker triggers CVE-2026-90173 vulnerability with a crafted request or payload

Execution

Vulnerability exploited to perform unauthorized actions on the target system

Impact

Depending on vulnerability type, attacker achieves data access, service disruption, or code execution

MITRE ATT&CK Techniques

T1190 Exploit Public-Facing Application

Initial Access

Public-facing application vulnerability exploited for initial access

T1203 Exploitation for Client Execution

Execution

Vulnerability exploited to execute attacker-controlled code

Indicators of Compromise

Type	Value	Description
user_agent	`Mozilla/5.0 (compatible; exploit/1.0)`	Generic exploit scanner user agent pattern
url	`/api/vuln-endpoint?payload=<malicious>`	Exploit attempt against application endpoint — monitor access logs for anomalous params

Remediation

1. Apply vendor-supplied security patches immediately. 2. If patches are unavailable, apply recommended mitigations from the vendor advisory. 3. Enable WAF rules or IDS signatures to detect exploitation attempts. 4. Monitor logs for indicators of compromise listed above. 5. Implement network segmentation to limit blast radius if exploitation occurs. 6. Subscribe to vendor security advisories for this product.

Quick Facts

CVE ID	CVE-2026-90173
CVSS Score	9.8
Vector	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`
Published	2026-09-17
Exploited	No
CISA KEV	No
PoC	Available

References

External Resources

NVD Entry BleepingComputer The Hacker News