{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2024-46847", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-09-11T15:12:18.290Z", "datePublished": "2024-09-27T12:39:39.550Z", "dateUpdated": "2026-08-05T11:38:58.890Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:38:58.890Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm: vmalloc: ensure vmap_block is initialised before adding to queue\n\nCommit 8c61291fd850 (\"mm: fix incorrect vbq reference in\npurge_fragmented_block\") extended the 'vmap_block' structure to contain a\n'cpu' field which is set at allocation time to the id of the initialising\nCPU.\n\nWhen a new 'vmap_block' is being instantiated by new_vmap_block(), the\npartially initialised structure is added to the local 'vmap_block_queue'\nxarray before the 'cpu' field has been initialised. If another CPU is\nconcurrently walking the xarray (e.g. via vm_unmap_aliases()), then it\nmay perform an out-of-bounds access to the remote queue thanks to an\nuninitialised index.\n\nThis has been observed as UBSAN errors in Android:\n\n | Internal error: UBSAN: array index out of bounds: 00000000f2005512 [#1] PREEMPT SMP\n |\n | Call trace:\n | purge_fragmented_block+0x204/0x21c\n | _vm_unmap_aliases+0x170/0x378\n | vm_unmap_aliases+0x1c/0x28\n | change_memory_common+0x1dc/0x26c\n | set_memory_ro+0x18/0x24\n | module_enable_ro+0x98/0x238\n | do_init_module+0x1b0/0x310\n\nMove the initialisation of 'vb->cpu' in new_vmap_block() ahead of the\naddition to the xarray." } ], "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 vulnerable code is core mm/vmalloc block allocation, reached through ordinary local syscall activity (read/write of compressed f2fs/erofs files, dma-buf/V4L2 buffer mapping, vmalloc/vfree churn). No network protocol handler reaches it.\nAC:L - The attacker controls both sides of the race — one thread drives vm_map_ram()/new_vmap_block() while another drives vm_unmap_aliases() on a different CPU — and the window is fully preemptible (no locks held, RCU section already exited), so it can be widened and retried indefinitely; it was observed triggering spontaneously in production Android without any attacker.\nPR:L - Every path to both sides of the race (f2fs/erofs compressed file I/O, udmabuf, videobuf2, vfree of VM_FLUSH_RESET_PERMS areas) is available to a plain unprivileged local user with no capability check anywhere along the trace.\nUI:N - The attacker's own threads perform all required operations; no victim action, mount, or file open by another user is needed.\nS:U - The uninitialized read, the out-of-bounds array access and the resulting crash all occur within the kernel's own security authority, with no crossing of a VM, IOMMU or sandbox boundary.\nC:H - __per_cpu_offset[vb->cpu] is an out-of-bounds read with an unbounded 32-bit index (up to ~32 GiB past the array) that is attacker-groomable, since struct vmap_block lands in kmalloc-256 and the uninitialized cpu field can be pre-seeded via heap spray — an attacker-directed read of arbitrary kernel memory, not a bounded few-byte overread.\nI:H - The out-of-bounds load produces a fully wild vmap_block_queue pointer built from attacker-influenceable data, which is subsequently used as a lock/list target inside purge_fragmented_block(), giving corruption of memory at an attacker-steered offset.\nA:H - The bug is a confirmed kernel panic — UBSAN array-index trap on Android, or an unhandled kernel page fault on the wild __per_cpu_offset[] load — and the oops happens while holding vmap_purge_lock and vb->lock inside an RCU read section, permanently deadlocking the vmap layer for all subsequent vmalloc/vfree." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "mm/vmalloc.c" ], "versions": [ { "version": "88e0ad40d08a73a74c597e69f4cd2d1fba3838b5", "lessThan": "1b2770e27d6d952f491bb362b657e5b2713c3efd", "status": "affected", "versionType": "git" }, { "version": "8c61291fd8500e3b35c7ec0c781b273d8cc96cde", "lessThan": "6cf74e0e5e3ab5d5c9defb4c73dad54d52224671", "status": "affected", "versionType": "git" }, { "version": "8c61291fd8500e3b35c7ec0c781b273d8cc96cde", "lessThan": "3e3de7947c751509027d26b679ecd243bc9db255", "status": "affected", "versionType": "git" }, { "version": "9983b81579be3403f5cc44b11f66c6c8bea6547f", "status": "affected", "versionType": "git" }, { "version": "6.6.37", "lessThan": "6.6.51", "status": "affected", "versionType": "semver" }, { "version": "6.9.8", "lessThan": "6.10", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "mm/vmalloc.c" ], "versions": [ { "version": "6.10", "status": "affected" }, { "version": "0", "lessThan": "6.10", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.51", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.10.10", "lessThanOrEqual": "6.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.11", "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": "6.6.37", "versionEndExcluding": "6.6.51" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.10", "versionEndExcluding": "6.10.10" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.10", "versionEndExcluding": "6.11" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9.8" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/1b2770e27d6d952f491bb362b657e5b2713c3efd" }, { "url": "https://git.kernel.org/stable/c/6cf74e0e5e3ab5d5c9defb4c73dad54d52224671" }, { "url": "https://git.kernel.org/stable/c/3e3de7947c751509027d26b679ecd243bc9db255" } ], "title": "mm: vmalloc: ensure vmap_block is initialised before adding to queue", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "timestamp": "2024-09-29T13:58:55.254929Z", "id": "CVE-2024-46847", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "role": "CISA Coordinator", "version": "2.0.3" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-09-29T13:58:59.658Z" } } ] } }