{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-39945","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2025-04-16T07:20:57.148Z","datePublished":"2025-10-04T07:31:07.109Z","dateUpdated":"2026-08-05T12:06:20.222Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T12:06:20.222Z"},"descriptions":[{"lang":"en","value":"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->dev; //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."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The vulnerable teardown path is reached only through local administrative operations on the netdev (link down, MTU/ring change, driver unbind, netns move) and local iSCSI/FCoE offload management; no remotely supplied data reaches `cnic_cm_stop_bnx2x_hw()` or `cnic_delete_task()`.\nAC:L - The attacker controls both sides of the race — issuing iSCSI/FCoE connection destroys keeps `delete_task` in its 10 ms self-requeue cycle for the entire 2-second grace window while the interface-down is triggered, giving hundreds of attempts per try, and holding the cnic UIO chardev open stretches `cnic_stop_hw()`'s wait loop to 1.5 s to widen the window further.\nPR:L - In the delegated-NIC container deployment, a bnx2x port placed into a network namespace lets a user-namespace-root (unprivileged host user) with `CAP_NET_ADMIN` over that netns drive `NETDEV_GOING_DOWN` and, via netns teardown/device migration, the `NETDEV_UNREGISTER` that reaches `cnic_free_dev()` — so no real host root is needed for the free side.\nUI:N - The attacker performs both the connection-destroy activity and the interface teardown; no victim action or cooperation is required at any point.\nS:U - The use-after-free corrupts kernel slab memory and is exploited within the kernel's own security authority, with no crossing of a hypervisor, IOMMU, or sandbox boundary.\nC:H - The freed `cnic_dev`/`cnic_local` chunk and `cp->ctx_tbl` can be reclaimed by attacker-sprayed data, and the surviving work reads function pointers, DMA addresses, and ULP handles out of that freed memory, giving a path to disclose arbitrary kernel memory.\nI:H - `cnic_delete_task()` performs `test_and_clear_bit()` writes into the freed `ctx_tbl`, `kfree()`s pointers read from freed memory (arbitrary-free primitive), and makes an indirect call through `cp->ethdev->drv_ctl` located in the freed allocation — a control-flow hijack primitive after heap grooming.\nA:H - The stale `delayed_work` timer is armed on `kfree()`d memory and the callback dereferences freed structures, so even an unsuccessful exploitation attempt reliably produces slab corruption, an oops, or a kernel panic."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/ethernet/broadcom/cnic.c"],"versions":[{"version":"fdf24086f4752aee5dfb40143c736250df017820","lessThan":"fde6e73189f40ebcf0633aed2b68e731c25f3aa3","status":"affected","versionType":"git"},{"version":"fdf24086f4752aee5dfb40143c736250df017820","lessThan":"7b6a5b0a6b392263c3767fc945b311ea04b34bbd","status":"affected","versionType":"git"},{"version":"fdf24086f4752aee5dfb40143c736250df017820","lessThan":"0405055930264ea8fd26f4131466fa7652e5e47d","status":"affected","versionType":"git"},{"version":"fdf24086f4752aee5dfb40143c736250df017820","lessThan":"e1fcd4a9c09feac0902a65615e866dbf22616125","status":"affected","versionType":"git"},{"version":"fdf24086f4752aee5dfb40143c736250df017820","lessThan":"8eeb2091e72d75df8ceaa2172638d61b4cf8929a","status":"affected","versionType":"git"},{"version":"fdf24086f4752aee5dfb40143c736250df017820","lessThan":"6e33a7eed587062ca8161ad1f4584882a860d697","status":"affected","versionType":"git"},{"version":"fdf24086f4752aee5dfb40143c736250df017820","lessThan":"0627e1481676669cae2df0d85b5ff13e7d24c390","status":"affected","versionType":"git"},{"version":"fdf24086f4752aee5dfb40143c736250df017820","lessThan":"cfa7d9b1e3a8604afc84e9e51d789c29574fb216","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/ethernet/broadcom/cnic.c"],"versions":[{"version":"2.6.37","status":"affected"},{"version":"0","lessThan":"2.6.37","status":"unaffected","versionType":"semver"},{"version":"5.4.300","lessThanOrEqual":"5.4.*","status":"unaffected","versionType":"semver"},{"version":"5.10.245","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.194","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.154","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.108","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.49","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.16.9","lessThanOrEqual":"6.16.*","status":"unaffected","versionType":"semver"},{"version":"6.17","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.37","versionEndExcluding":"5.4.300"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.37","versionEndExcluding":"5.10.245"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.37","versionEndExcluding":"5.15.194"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.37","versionEndExcluding":"6.1.154"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.37","versionEndExcluding":"6.6.108"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.37","versionEndExcluding":"6.12.49"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.37","versionEndExcluding":"6.16.9"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.37","versionEndExcluding":"6.17"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/fde6e73189f40ebcf0633aed2b68e731c25f3aa3"},{"url":"https://git.kernel.org/stable/c/7b6a5b0a6b392263c3767fc945b311ea04b34bbd"},{"url":"https://git.kernel.org/stable/c/0405055930264ea8fd26f4131466fa7652e5e47d"},{"url":"https://git.kernel.org/stable/c/e1fcd4a9c09feac0902a65615e866dbf22616125"},{"url":"https://git.kernel.org/stable/c/8eeb2091e72d75df8ceaa2172638d61b4cf8929a"},{"url":"https://git.kernel.org/stable/c/6e33a7eed587062ca8161ad1f4584882a860d697"},{"url":"https://git.kernel.org/stable/c/0627e1481676669cae2df0d85b5ff13e7d24c390"},{"url":"https://git.kernel.org/stable/c/cfa7d9b1e3a8604afc84e9e51d789c29574fb216"}],"title":"cnic: Fix use-after-free bugs in cnic_delete_task","x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2025-39945","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-06-10T20:41:21.785248Z"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-06-11T18:44:11.566Z"}}]}}