{"id":"CVE-2025-39945","summary":"cnic: Fix use-after-free bugs in cnic_delete_task","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ncnic: Fix use-after-free bugs in cnic_delete_task\n\nThe original code uses cancel_delayed_work() in cnic_cm_stop_bnx2x_hw(),\nwhich does not guarantee that the delayed work item 'delete_task' has\nfully completed if it was already running. Additionally, the delayed work\nitem is cyclic, the flush_workqueue() in cnic_cm_stop_bnx2x_hw() only\nblocks and waits for work items that were already queued to the\nworkqueue prior to its invocation. Any work items submitted after\nflush_workqueue() is called are not included in the set of tasks that the\nflush operation awaits. This means that after the cyclic work items have\nfinished executing, a delayed work item may still exist in the workqueue.\nThis leads to use-after-free scenarios where the cnic_dev is deallocated\nby cnic_free_dev(), while delete_task remains active and attempt to\ndereference cnic_dev in cnic_delete_task().\n\nA typical race condition is illustrated below:\n\nCPU 0 (cleanup)              | CPU 1 (delayed work callback)\ncnic_netdev_event()          |\n  cnic_stop_hw()             | cnic_delete_task()\n    cnic_cm_stop_bnx2x_hw()  | ...\n      cancel_delayed_work()  | /* the queue_delayed_work()\n      flush_workqueue()      |    executes after flush_workqueue()*/\n                             | queue_delayed_work()\n  cnic_free_dev(dev)//free   | cnic_delete_task() //new instance\n                             |   dev = cp-\u003edev; //use\n\nReplace cancel_delayed_work() with cancel_delayed_work_sync() to ensure\nthat the cyclic delayed work item is properly canceled and that any\nongoing execution of the work item completes before the cnic_dev is\ndeallocated. Furthermore, since cancel_delayed_work_sync() uses\n__flush_work(work, true) to synchronously wait for any currently\nexecuting instance of the work item to finish, the flush_workqueue()\nbecomes redundant and should be removed.\n\nThis bug was identified through static analysis. To reproduce the issue\nand validate the fix, I simulated the cnic PCI device in QEMU and\nintroduced intentional delays — such as inserting calls to ssleep()\nwithin the cnic_delete_task() function — to increase the likelihood\nof triggering the bug.","modified":"2026-03-20T12:43:06.829500Z","published":"2025-10-04T07:31:07.109Z","related":["MGASA-2025-0309","MGASA-2025-0310","SUSE-SU-2025:21040-1","SUSE-SU-2025:21052-1","SUSE-SU-2025:21056-1","SUSE-SU-2025:21064-1","SUSE-SU-2025:21074-1","SUSE-SU-2025:21139-1","SUSE-SU-2025:21179-1","SUSE-SU-2025:4057-1","SUSE-SU-2025:4111-1","SUSE-SU-2025:4128-1","SUSE-SU-2025:4132-1","SUSE-SU-2025:4139-1","SUSE-SU-2025:4140-1","SUSE-SU-2025:4141-1","SUSE-SU-2025:4149-1","SUSE-SU-2025:4189-1","SUSE-SU-2025:4301-1","SUSE-SU-2025:4320-1","openSUSE-SU-2025:20081-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/39xxx/CVE-2025-39945.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/0405055930264ea8fd26f4131466fa7652e5e47d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/0627e1481676669cae2df0d85b5ff13e7d24c390"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6e33a7eed587062ca8161ad1f4584882a860d697"},{"type":"WEB","url":"https://git.kernel.org/stable/c/7b6a5b0a6b392263c3767fc945b311ea04b34bbd"},{"type":"WEB","url":"https://git.kernel.org/stable/c/8eeb2091e72d75df8ceaa2172638d61b4cf8929a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/cfa7d9b1e3a8604afc84e9e51d789c29574fb216"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e1fcd4a9c09feac0902a65615e866dbf22616125"},{"type":"WEB","url":"https://git.kernel.org/stable/c/fde6e73189f40ebcf0633aed2b68e731c25f3aa3"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/39xxx/CVE-2025-39945.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-39945"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"fdf24086f4752aee5dfb40143c736250df017820"},{"fixed":"fde6e73189f40ebcf0633aed2b68e731c25f3aa3"},{"fixed":"7b6a5b0a6b392263c3767fc945b311ea04b34bbd"},{"fixed":"0405055930264ea8fd26f4131466fa7652e5e47d"},{"fixed":"e1fcd4a9c09feac0902a65615e866dbf22616125"},{"fixed":"8eeb2091e72d75df8ceaa2172638d61b4cf8929a"},{"fixed":"6e33a7eed587062ca8161ad1f4584882a860d697"},{"fixed":"0627e1481676669cae2df0d85b5ff13e7d24c390"},{"fixed":"cfa7d9b1e3a8604afc84e9e51d789c29574fb216"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-39945.json"}}],"schema_version":"1.7.5"}