{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-40251", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T07:20:57.181Z", "datePublished": "2025-12-04T16:08:13.710Z", "dateUpdated": "2026-08-05T12:08:53.761Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:08:53.761Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndevlink: rate: Unset parent pointer in devl_rate_nodes_destroy\n\nThe function devl_rate_nodes_destroy is documented to \"Unset parent for\nall rate objects\". However, it was only calling the driver-specific\n`rate_leaf_parent_set` or `rate_node_parent_set` ops and decrementing\nthe parent's refcount, without actually setting the\n`devlink_rate->parent` pointer to NULL.\n\nThis leaves a dangling pointer in the `devlink_rate` struct, which cause\nrefcount error in netdevsim[1] and mlx5[2]. In addition, this is\ninconsistent with the behavior of `devlink_nl_rate_parent_node_set`,\nwhere the parent pointer is correctly cleared.\n\nThis patch fixes the issue by explicitly setting `devlink_rate->parent`\nto NULL after notifying the driver, thus fulfilling the function's\ndocumented behavior for all rate objects.\n\n[1]\nrepro steps:\necho 1 > /sys/bus/netdevsim/new_device\ndevlink dev eswitch set netdevsim/netdevsim1 mode switchdev\necho 1 > /sys/bus/netdevsim/devices/netdevsim1/sriov_numvfs\ndevlink port function rate add netdevsim/netdevsim1/test_node\ndevlink port function rate set netdevsim/netdevsim1/128 parent test_node\necho 1 > /sys/bus/netdevsim/del_device\n\ndmesg:\nrefcount_t: decrement hit 0; leaking memory.\nWARNING: CPU: 8 PID: 1530 at lib/refcount.c:31 refcount_warn_saturate+0x42/0xe0\nCPU: 8 UID: 0 PID: 1530 Comm: bash Not tainted 6.18.0-rc4+ #1 NONE\nHardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014\nRIP: 0010:refcount_warn_saturate+0x42/0xe0\nCall Trace:\n \n devl_rate_leaf_destroy+0x8d/0x90\n __nsim_dev_port_del+0x6c/0x70 [netdevsim]\n nsim_dev_reload_destroy+0x11c/0x140 [netdevsim]\n nsim_drv_remove+0x2b/0xb0 [netdevsim]\n device_release_driver_internal+0x194/0x1f0\n bus_remove_device+0xc6/0x130\n device_del+0x159/0x3c0\n device_unregister+0x1a/0x60\n del_device_store+0x111/0x170 [netdevsim]\n kernfs_fop_write_iter+0x12e/0x1e0\n vfs_write+0x215/0x3d0\n ksys_write+0x5f/0xd0\n do_syscall_64+0x55/0x10f0\n entry_SYSCALL_64_after_hwframe+0x4b/0x53\n\n[2]\ndevlink dev eswitch set pci/0000:08:00.0 mode switchdev\ndevlink port add pci/0000:08:00.0 flavour pcisf pfnum 0 sfnum 1000\ndevlink port function rate add pci/0000:08:00.0/group1\ndevlink port function rate set pci/0000:08:00.0/32768 parent group1\nmodprobe -r mlx5_ib mlx5_fwctl mlx5_core\n\ndmesg:\nrefcount_t: decrement hit 0; leaking memory.\nWARNING: CPU: 7 PID: 16151 at lib/refcount.c:31 refcount_warn_saturate+0x42/0xe0\nCPU: 7 UID: 0 PID: 16151 Comm: bash Not tainted 6.17.0-rc7_for_upstream_min_debug_2025_10_02_12_44 #1 NONE\nHardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014\nRIP: 0010:refcount_warn_saturate+0x42/0xe0\nCall Trace:\n \n devl_rate_leaf_destroy+0x8d/0x90\n mlx5_esw_offloads_devlink_port_unregister+0x33/0x60 [mlx5_core]\n mlx5_esw_offloads_unload_rep+0x3f/0x50 [mlx5_core]\n mlx5_eswitch_unload_sf_vport+0x40/0x90 [mlx5_core]\n mlx5_sf_esw_event+0xc4/0x120 [mlx5_core]\n notifier_call_chain+0x33/0xa0\n blocking_notifier_call_chain+0x3b/0x50\n mlx5_eswitch_disable_locked+0x50/0x110 [mlx5_core]\n mlx5_eswitch_disable+0x63/0x90 [mlx5_core]\n mlx5_unload+0x1d/0x170 [mlx5_core]\n mlx5_uninit_one+0xa2/0x130 [mlx5_core]\n remove_one+0x78/0xd0 [mlx5_core]\n pci_device_remove+0x39/0xa0\n device_release_driver_internal+0x194/0x1f0\n unbind_store+0x99/0xa0\n kernfs_fop_write_iter+0x12e/0x1e0\n vfs_write+0x215/0x3d0\n ksys_write+0x5f/0xd0\n do_syscall_64+0x53/0x1f0\n entry_SYSCALL_64_after_hwframe+0x4b/0x53" } ], "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 dangling `devlink_rate->parent` is dereferenced from the devlink generic-netlink interface (`DEVLINK_CMD_RATE_GET` dump) and from local device/eswitch reconfiguration paths reached via netlink and sysfs. No network packet processing is involved, so this is local-only.\nAC:L - Once `devl_rate_nodes_destroy()` runs (SR-IOV teardown, eswitch mode change, driver reload — routine in SR-IOV/DPU cloud hosts), the stale parent pointer persists in surviving leaf rate objects, so there is no race to win: the attacker sprays the 120-byte kmalloc-128 slot and then deterministically triggers the deref with an unprivileged `devlink port function rate show`. The reproducers in the commit message are deterministic one-shot command sequences.\nPR:L - The vulnerable dereference sites — `devlink_nl_rate_fill()` reading `devlink_rate->parent->name` and emitting it to userspace — sit behind `DEVLINK_CMD_RATE_GET`, which carries only `GENL_CMD_CAP_DO|DUMP` with no `GENL_ADMIN_PERM` and no family-level gate, so an ordinary unprivileged local user reaches the freed object and obtains the read primitive. Only the state-creating teardown needs CAP_NET_ADMIN, and that occurs as routine orchestration activity on the affected mlx5/ice/netdevsim hosts.\nUI:N - No victim must open a file, mount a filesystem, or interact in any way; the attacker issues the netlink dump (or the whole command sequence) themselves. Exploitation completes entirely within attacker-issued syscalls.\nS:U - The use-after-free read and write are confined to kernel slab memory under the same security authority as the kernel itself. No VM, IOMMU, or sandbox boundary is crossed.\nC:H - `nla_put_string(msg, DEVLINK_ATTR_RATE_PARENT_NODE_NAME, devlink_rate->parent->name)` loads a pointer from offset 64 of the freed `struct devlink_rate` and copies the string it points at back to userspace; after reclaiming the kmalloc-128 slot with controlled data this is an unbounded arbitrary kernel-memory read delivered over an unprivileged netlink dump.\nI:H - `devl_rate_leaf_destroy()` performs `refcount_dec()` on offset 72 of the freed object, giving a controlled decrement primitive against whatever kmalloc-128 object reclaims the slot — dropping a live object's refcount to zero yields a second use-after-free and the standard heap-spray path to arbitrary write and control-flow hijack.\nA:H - Even without reclamation the bug reliably produces `refcount_warn_saturate` WARNINGs (\"decrement hit 0; leaking memory\") as shown in both netdevsim and mlx5 traces, which panic the box under `panic_on_warn`; with a reclaimed slot the corrupted refcount causes premature frees, slab corruption, and oops on the subsequent dangling-pointer string dereference." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/devlink/rate.c" ], "versions": [ { "version": "d7555984507822458b32a6405881038241d140be", "lessThan": "90e51e20bcec9bff5b2421ce1bd95704764655f5", "status": "affected", "versionType": "git" }, { "version": "d7555984507822458b32a6405881038241d140be", "lessThan": "715d9cda646a8a38ea8b2bb5afb679a7464055e2", "status": "affected", "versionType": "git" }, { "version": "d7555984507822458b32a6405881038241d140be", "lessThan": "c70df6c17d389cc743f0eb30160e2d6bc6910db8", "status": "affected", "versionType": "git" }, { "version": "d7555984507822458b32a6405881038241d140be", "lessThan": "542f45486f1ce2d2dde75bd85aca0389ef7046c3", "status": "affected", "versionType": "git" }, { "version": "d7555984507822458b32a6405881038241d140be", "lessThan": "f94c1a114ac209977bdf5ca841b98424295ab1f0", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/devlink/rate.c" ], "versions": [ { "version": "5.14", "status": "affected" }, { "version": "0", "lessThan": "5.14", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.164", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.118", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.60", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.17.10", "lessThanOrEqual": "6.17.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18", "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": "5.14", "versionEndExcluding": "6.1.164" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "6.6.118" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "6.12.60" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "6.17.10" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "6.18" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/90e51e20bcec9bff5b2421ce1bd95704764655f5" }, { "url": "https://git.kernel.org/stable/c/715d9cda646a8a38ea8b2bb5afb679a7464055e2" }, { "url": "https://git.kernel.org/stable/c/c70df6c17d389cc743f0eb30160e2d6bc6910db8" }, { "url": "https://git.kernel.org/stable/c/542f45486f1ce2d2dde75bd85aca0389ef7046c3" }, { "url": "https://git.kernel.org/stable/c/f94c1a114ac209977bdf5ca841b98424295ab1f0" } ], "title": "devlink: rate: Unset parent pointer in devl_rate_nodes_destroy", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "x_adpType": "supplier", "providerMetadata": { "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "shortName": "siemens-SADP", "dateUpdated": "2026-06-02T13:00:01.139Z" }, "affected": [ { "vendor": "Siemens", "product": "RUGGEDCOM RST2428P", "versions": [ { "status": "affected", "version": "0", "lessThan": "V4.0", "versionType": "custom" } ], "defaultStatus": "unknown" } ], "references": [ { "url": "https://cert-portal.siemens.com/productcert/html/ssa-253495.html" } ] }, { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2025-40251", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "version": "2.0.3", "timestamp": "2026-06-10T20:41:14.789338Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-06-11T18:44:10.307Z" } } ] } }