CVE-2025-21991

{"cve": {"data_type": "CVE", "references": {"reference_data": [{"url": "https://git.kernel.org/stable/c/18b5d857c6496b78ead2fd10001b81ae32d30cac", "name": "https://git.kernel.org/stable/c/18b5d857c6496b78ead2fd10001b81ae32d30cac", "tags": ["Patch"], "refsource": ""}, {"url": "https://git.kernel.org/stable/c/488ffc0cac38f203979f83634236ee53251ce593", "name": "https://git.kernel.org/stable/c/488ffc0cac38f203979f83634236ee53251ce593", "tags": ["Patch"], "refsource": ""}, {"url": "https://git.kernel.org/stable/c/5ac295dfccb5b015493f86694fa13a0dde4d3665", "name": "https://git.kernel.org/stable/c/5ac295dfccb5b015493f86694fa13a0dde4d3665", "tags": ["Patch"], "refsource": ""}, {"url": "https://git.kernel.org/stable/c/985a536e04bbfffb1770df43c6470f635a6b1073", "name": "https://git.kernel.org/stable/c/985a536e04bbfffb1770df43c6470f635a6b1073", "tags": ["Patch"], "refsource": ""}, {"url": "https://git.kernel.org/stable/c/d509c4731090ebd9bbdb72c70a2d70003ae81f4f", "name": "https://git.kernel.org/stable/c/d509c4731090ebd9bbdb72c70a2d70003ae81f4f", "tags": ["Patch"], "refsource": ""}, {"url": "https://git.kernel.org/stable/c/e3e89178a9f4a80092578af3ff3c8478f9187d59", "name": "https://git.kernel.org/stable/c/e3e89178a9f4a80092578af3ff3c8478f9187d59", "tags": ["Patch"], "refsource": ""}, {"url": "https://git.kernel.org/stable/c/e686349cc19e800dac8971929089ba5ff59abfb0", "name": "https://git.kernel.org/stable/c/e686349cc19e800dac8971929089ba5ff59abfb0", "tags": ["Patch"], "refsource": ""}, {"url": "https://git.kernel.org/stable/c/ec52240622c4d218d0240079b7c1d3ec2328a9f4", "name": "https://git.kernel.org/stable/c/ec52240622c4d218d0240079b7c1d3ec2328a9f4", "tags": ["Patch"], "refsource": ""}]}, "data_format": "MITRE", "description": {"description_data": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nx86/microcode/AMD: Fix out-of-bounds on systems with CPU-less NUMA nodes\n\nCurrently, load_microcode_amd() iterates over all NUMA nodes, retrieves their\nCPU masks and unconditionally accesses per-CPU data for the first CPU of each\nmask.\n\nAccording to Documentation/admin-guide/mm/numaperf.rst:\n\n \"Some memory may share the same node as a CPU, and others are provided as\n memory only nodes.\"\n\nTherefore, some node CPU masks may be empty and wouldn't have a \"first CPU\".\n\nOn a machine with far memory (and therefore CPU-less NUMA nodes):\n- cpumask_of_node(nid) is 0\n- cpumask_first(0) is CONFIG_NR_CPUS\n- cpu_data(CONFIG_NR_CPUS) accesses the cpu_info per-CPU array at an\n index that is 1 out of bounds\n\nThis does not have any security implications since flashing microcode is\na privileged operation but I believe this has reliability implications by\npotentially corrupting memory while flashing a microcode update.\n\nWhen booting with CONFIG_UBSAN_BOUNDS=y on an AMD machine that flashes\na microcode update. I get the following splat:\n\n UBSAN: array-index-out-of-bounds in arch/x86/kernel/cpu/microcode/amd.c:X:Y\n index 512 is out of range for type 'unsigned long[512]'\n [...]\n Call Trace:\n dump_stack\n __ubsan_handle_out_of_bounds\n load_microcode_amd\n request_microcode_amd\n reload_store\n kernfs_fop_write_iter\n vfs_write\n ksys_write\n do_syscall_64\n entry_SYSCALL_64_after_hwframe\n\nChange the loop to go over only NUMA nodes which have CPUs before determining\nwhether the first CPU on the respective node needs microcode update.\n\n [ bp: Massage commit message, fix typo. ]"}]}, "problemtype": {"problemtype_data": [{"description": [{"lang": "en", "value": "CWE-129"}]}]}, "data_version": "4.0", "CVE_data_meta": {"ID": "CVE-2025-21991", "ASSIGNER": "cve@kernel.org"}}, "impact": {"baseMetricV3": {"cvssV3": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.8, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}, "impactScore": 5.9, "exploitabilityScore": 1.8}}, "publishedDate": "2025-04-02T13:15Z", "configurations": {"nodes": [{"children": [], "operator": "OR", "cpe_match": [{"cpe23Uri": "cpe:2.3:o:linux:linux_kernel:6.14:rc1:*:*:*:*:*:*", "cpe_name": [], "vulnerable": true}, {"cpe23Uri": "cpe:2.3:o:linux:linux_kernel:6.14:rc2:*:*:*:*:*:*", "cpe_name": [], "vulnerable": true}, {"cpe23Uri": "cpe:2.3:o:linux:linux_kernel:6.14:rc3:*:*:*:*:*:*", "cpe_name": [], "vulnerable": true}, {"cpe23Uri": "cpe:2.3:o:linux:linux_kernel:6.14:rc4:*:*:*:*:*:*", "cpe_name": [], "vulnerable": true}, {"cpe23Uri": "cpe:2.3:o:linux:linux_kernel:6.14:rc5:*:*:*:*:*:*", "cpe_name": [], "vulnerable": true}, {"cpe23Uri": "cpe:2.3:o:linux:linux_kernel:6.14:rc6:*:*:*:*:*:*", "cpe_name": [], "vulnerable": true}, {"cpe23Uri": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": true, "versionEndExcluding": "4.15", "versionStartIncluding": "4.14.308"}, {"cpe23Uri": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": true, "versionEndExcluding": "4.20", "versionStartIncluding": "4.19.276"}, {"cpe23Uri": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": true, "versionEndExcluding": "5.5", "versionStartIncluding": "5.4.235"}, {"cpe23Uri": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": true, "versionEndExcluding": "5.11", "versionStartIncluding": "5.10.173"}, {"cpe23Uri": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": true, "versionEndExcluding": "5.16", "versionStartIncluding": "5.15.99"}, {"cpe23Uri": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": true, "versionEndExcluding": "6.1.132", "versionStartIncluding": "6.1.16"}, {"cpe23Uri": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": true, "versionEndExcluding": "6.6.84", "versionStartIncluding": "6.2.3"}, {"cpe23Uri": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": true, "versionEndExcluding": "6.12.20", "versionStartIncluding": "6.7"}, {"cpe23Uri": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": true, "versionEndExcluding": "6.13.8", "versionStartIncluding": "6.13"}]}], "CVE_data_version": "4.0"}, "lastModifiedDate": "2025-04-10T13:24Z"}