{"cve":"CVE-2024-46847","nvd":{"published":"2024-09-27T13:15:16.570","modified":"2026-08-04T11:20:32.823","status":"Modified","description":"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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":["CWE-129"],"references":["https://git.kernel.org/stable/c/1b2770e27d6d952f491bb362b657e5b2713c3efd","https://git.kernel.org/stable/c/3e3de7947c751509027d26b679ecd243bc9db255","https://git.kernel.org/stable/c/6cf74e0e5e3ab5d5c9defb4c73dad54d52224671"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:54:38.012257375+00:00"},"epss":{"cve":"CVE-2024-46847","score":0.00227,"percentile":0.13538,"date":"2026-11-01"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}