{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-39990", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T07:20:57.150Z", "datePublished": "2025-10-15T07:56:07.295Z", "dateUpdated": "2026-08-05T12:06:56.969Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:06:56.969Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Check the helper function is valid in get_helper_proto\n\nkernel test robot reported verifier bug [1] where the helper func\npointer could be NULL due to disabled config option.\n\nAs Alexei suggested we could check on that in get_helper_proto\ndirectly. Marking tail_call helper func with BPF_PTR_POISON,\nbecause it is unused by design.\n\n [1] https://lore.kernel.org/oe-lkp/202507160818.68358831-lkp@intel.com" } ], "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 vulnerability is reached only through the local `bpf(BPF_PROG_LOAD)` syscall, which is used to submit the crafted program to the verifier. There is no remote or adjacent-network path into `get_helper_proto()`.\nAC:L - On an affected build the attacker deterministically triggers the bug every time by loading a program that calls a helper whose weak proto is zeroed — no race, no memory-layout dependency, no unpredictable state. Both the `verifier_bug()` WARN path and the `bpf_get_branch_snapshot` inline path are fully under the attacker's control via the program bytecode.\nPR:L - Program load plus `CAP_PERFMON`/`CAP_BPF` is required, but `CAP_PERFMON` is a narrow, non-root capability commonly granted to unprivileged profiling and BPF observability daemons, and `bpf_token_capable()` explicitly makes it delegable to unprivileged users inside user namespaces via bpffs BPF tokens. This is an ordinary low-privileged account boundary, not init-namespace root.\nUI:N - The attacker loads and exercises the BPF program entirely on their own; no other user or administrator has to perform any action.\nS:U - The corruption and the crash both occur inside the kernel that is already the security authority for the calling process — a conventional local kernel privilege-escalation/DoS, with no VM, IOMMU, or sandbox boundary crossed.\nC:H - With all `arg_type[]` zeroed to `ARG_DONTCARE` the verifier validates nothing, and the inlined `bpf_get_branch_snapshot` copies LBR records (kernel from/to instruction pointers) to an attacker-chosen destination that can be a readable BPF map value, disclosing kernel text addresses and defeating KASLR; the same unvalidated-pointer primitive generalizes to broader kernel memory disclosure.\nI:H - `__intel_pmu_snapshot_branch_stack()` performs `memcpy(entries, cpuc->lbr_entries, 24 * cnt)` with `entries` an entirely unvalidated attacker-supplied scalar, giving an arbitrary kernel-memory write of up to several hundred bytes — a direct privilege-escalation primitive.\nA:H - The common path hits `verifier_bug()` → `BPF_WARN_ONCE`, which taints the kernel and panics outright on the many hardened/production and Android kernels that set `panic_on_warn=1`; the arbitrary-write path trivially oopses the kernel by targeting unmapped or critical memory." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/bpf/core.c", "kernel/bpf/verifier.c" ], "versions": [ { "version": "f470378c7562a2818b45ed11c98973f2b89eedd3", "lessThan": "3d429cb1278e995e22995ef117fa96d223a67e93", "status": "affected", "versionType": "git" }, { "version": "f470378c7562a2818b45ed11c98973f2b89eedd3", "lessThan": "6233715b4b714068d6c831d214a4e8792109875a", "status": "affected", "versionType": "git" }, { "version": "f470378c7562a2818b45ed11c98973f2b89eedd3", "lessThan": "e4414b01c1cd9887bbde92f946c1ba94e40d6d64", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/bpf/core.c", "kernel/bpf/verifier.c" ], "versions": [ { "version": "5.8", "status": "affected" }, { "version": "0", "lessThan": "5.8", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.50", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.16.10", "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": "5.8", "versionEndExcluding": "6.12.50" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.8", "versionEndExcluding": "6.16.10" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.8", "versionEndExcluding": "6.17" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/3d429cb1278e995e22995ef117fa96d223a67e93" }, { "url": "https://git.kernel.org/stable/c/6233715b4b714068d6c831d214a4e8792109875a" }, { "url": "https://git.kernel.org/stable/c/e4414b01c1cd9887bbde92f946c1ba94e40d6d64" } ], "title": "bpf: Check the helper function is valid in get_helper_proto", "x_generator": { "engine": "bippy-1.2.0" } } } }