{ "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" } } ] } }