{ "data_version": "4.0", "data_type": "CVE", "data_format": "MITRE", "CVE_data_meta": { "ID": "CVE-2025-21991", "ASSIGNER": "cve@kernel.org", "STATE": "PUBLIC" }, "description": { "description_data": [ { "lang": "eng", "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": "eng", "value": "n/a" } ] } ] }, "affects": { "vendor": { "vendor_data": [ { "vendor_name": "Linux", "product": { "product_data": [ { "product_name": "Linux", "version": { "version_data": [ { "version_affected": "<", "version_name": "979e197968a1e8f09bf0d706801dba4432f85ab3", "version_value": "d509c4731090ebd9bbdb72c70a2d70003ae81f4f" }, { "version_affected": "<", "version_name": "44a44b57e88f311c1415be1f567c50050913c149", "version_value": "985a536e04bbfffb1770df43c6470f635a6b1073" }, { "version_affected": "<", "version_name": "be2710deaed3ab1402379a2ede30a3754fe6767a", "version_value": "18b5d857c6496b78ead2fd10001b81ae32d30cac" }, { "version_affected": "<", "version_name": "d576547f489c935b9897d4acf8beee3325dea8a5", "version_value": "ec52240622c4d218d0240079b7c1d3ec2328a9f4" }, { "version_affected": "<", "version_name": "7ff6edf4fef38ab404ee7861f257e28eaaeed35f", "version_value": "e686349cc19e800dac8971929089ba5ff59abfb0" }, { "version_value": "not down converted", "x_cve_json_5_version_data": { "versions": [ { "version": "6.3", "status": "affected" }, { "version": "0", "lessThan": "6.3", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.292", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.236", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.180", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.132", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.84", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.20", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.13.8", "lessThanOrEqual": "6.13.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.14", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ], "defaultStatus": "affected" } } ] } } ] } } ] } }, "references": { "reference_data": [ { "url": "https://git.kernel.org/stable/c/d509c4731090ebd9bbdb72c70a2d70003ae81f4f", "refsource": "MISC", "name": "https://git.kernel.org/stable/c/d509c4731090ebd9bbdb72c70a2d70003ae81f4f" }, { "url": "https://git.kernel.org/stable/c/985a536e04bbfffb1770df43c6470f635a6b1073", "refsource": "MISC", "name": "https://git.kernel.org/stable/c/985a536e04bbfffb1770df43c6470f635a6b1073" }, { "url": "https://git.kernel.org/stable/c/18b5d857c6496b78ead2fd10001b81ae32d30cac", "refsource": "MISC", "name": "https://git.kernel.org/stable/c/18b5d857c6496b78ead2fd10001b81ae32d30cac" }, { "url": "https://git.kernel.org/stable/c/ec52240622c4d218d0240079b7c1d3ec2328a9f4", "refsource": "MISC", "name": "https://git.kernel.org/stable/c/ec52240622c4d218d0240079b7c1d3ec2328a9f4" }, { "url": "https://git.kernel.org/stable/c/e686349cc19e800dac8971929089ba5ff59abfb0", "refsource": "MISC", "name": "https://git.kernel.org/stable/c/e686349cc19e800dac8971929089ba5ff59abfb0" }, { "url": "https://git.kernel.org/stable/c/488ffc0cac38f203979f83634236ee53251ce593", "refsource": "MISC", "name": "https://git.kernel.org/stable/c/488ffc0cac38f203979f83634236ee53251ce593" }, { "url": "https://git.kernel.org/stable/c/5ac295dfccb5b015493f86694fa13a0dde4d3665", "refsource": "MISC", "name": "https://git.kernel.org/stable/c/5ac295dfccb5b015493f86694fa13a0dde4d3665" }, { "url": "https://git.kernel.org/stable/c/e3e89178a9f4a80092578af3ff3c8478f9187d59", "refsource": "MISC", "name": "https://git.kernel.org/stable/c/e3e89178a9f4a80092578af3ff3c8478f9187d59" } ] }, "generator": { "engine": "bippy-7c5fe7eed585" } }