{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2025-40251 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2025-40251 is a high-severity vulnerability in Linux kernel, published on 4 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2025-40251 and fix it if it is affected.\n\nWhat it is: CVE-2025-40251 is a high-severity vulnerability in Linux kernel, published on 4 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2025-40251 in the wild and no public exploit code.\n\nAffected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2025-40251/ (Markdown: https://insights.sbomify.com/CVE-2025-40251/index.md)","id":"CVE-2025-40251","markdown":"https://insights.sbomify.com/CVE-2025-40251/index.md","name":"CVE-2025-40251","record":{"aliases":["AZL-71420","AZL-78395","BELL-CVE-2025-40251","DEBIAN-CVE-2025-40251","GHSA-4fxr-v6jm-9j9m","ROOT-OS-DEBIAN-12-CVE-2025-40251","ROOT-OS-DEBIAN-13-CVE-2025-40251","ROOT-OS-UBUNTU-2204-CVE-2025-40251","ROOT-OS-UBUNTU-2404-CVE-2025-40251","UBUNTU-CVE-2025-40251"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"A missing pointer cleanup in the Linux kernel devlink rate subsystem causes a dangling pointer, leading to refcount errors and potential system crashes.","user_interaction":"not_required","vuln_class":"null_dereference"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":7.8,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"cwes":[{"id":"CWE-476","name":"NULL Pointer Dereference"}],"description":"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-\u003eparent` 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-\u003eparent`\nto NULL after notifying the driver, thus fulfilling the function's\ndocumented behavior for all rate objects.\n\n[1]\nrepro steps:\necho 1 \u003e /sys/bus/netdevsim/new_device\ndevlink dev eswitch set netdevsim/netdevsim1 mode switchdev\necho 1 \u003e /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 \u003e /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 \u003cTASK\u003e\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 \u003cTASK\u003e\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","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"devlink: rate: Unset parent pointer in devl_rate_nodes_destroy","id":"CVE-2025-40251","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"null_dereference","year":"2025"},"n_packages":0,"n_references":5,"next":{"headline":"net: qlogic/qede: fix potential out-of-bounds read in qede_tpa_cont() and qede_tpa_end()","id":"CVE-2025-40252"},"packages":[],"prev":{"headline":"net/mlx5: Clean up only new IRQ glue on request_irq() failure","id":"CVE-2025-40250"},"products":["Linux"],"published":"2025-12-04","related":[{"cvss_score":8.8,"headline":"Linux Kernel Out-of-Bounds Write","id":"CVE-2026-53266","kev_date_added":"2026-09-18","published":"2026-06-25"},{"cvss_score":8.8,"headline":"Linux Kernel Improper Input Validation","id":"CVE-2013-6282","kev_date_added":"2022-09-15","published":"2013-11-19"},{"cvss_score":8.4,"headline":"Linux Kernel Heap-Based Buffer Overflow","id":"CVE-2022-0185","kev_date_added":"2024-08-21","published":"2022-02-11"},{"cvss_score":8.4,"headline":"Linux Kernel Privilege Escalation","id":"CVE-2013-2094","kev_date_added":"2022-09-15","published":"2013-05-14"},{"cvss_score":7.8,"headline":"Linux Kernel Unspecified","id":"CVE-2026-53362","kev_date_added":"2026-08-27","published":"2026-07-04"},{"cvss_score":7.8,"headline":"Linux Kernel Missing Initialization of a Variable","id":"CVE-2026-46300","kev_date_added":"2026-10-28","published":"2026-05-23"},{"cvss_score":7.8,"headline":"Linux Kernel Race Condition","id":"CVE-2025-39964","kev_date_added":"2026-09-18","published":"2025-10-13"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-08-05","vendors":["Linux"]},"summary":"A missing pointer cleanup in the Linux kernel devlink rate subsystem causes a dangling pointer, leading to refcount errors and potential system crashes.","url":"https://insights.sbomify.com/CVE-2025-40251/"}