{"cve":"CVE-2021-47497","nvd":{"published":"2024-05-22T09:15:11.513","modified":"2026-06-17T04:17:37.703","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnvmem: Fix shift-out-of-bound (UBSAN) with byte size cells\n\nIf a cell has 'nbits' equal to a multiple of BITS_PER_BYTE the logic\n\n *p &= GENMASK((cell->nbits%BITS_PER_BYTE) - 1, 0);\n\nwill become undefined behavior because nbits modulo BITS_PER_BYTE is 0, and we\nsubtract one from that making a large number that is then shifted more than the\nnumber of bits that fit into an unsigned long.\n\nUBSAN reports this problem:\n\n UBSAN: shift-out-of-bounds in drivers/nvmem/core.c:1386:8\n shift exponent 64 is too large for 64-bit type 'unsigned long'\n CPU: 6 PID: 7 Comm: kworker/u16:0 Not tainted 5.15.0-rc3+ #9\n Hardware name: Google Lazor (rev3+) with KB Backlight (DT)\n Workqueue: events_unbound deferred_probe_work_func\n Call trace:\n  dump_backtrace+0x0/0x170\n  show_stack+0x24/0x30\n  dump_stack_lvl+0x64/0x7c\n  dump_stack+0x18/0x38\n  ubsan_epilogue+0x10/0x54\n  __ubsan_handle_shift_out_of_bounds+0x180/0x194\n  __nvmem_cell_read+0x1ec/0x21c\n  nvmem_cell_read+0x58/0x94\n  nvmem_cell_read_variable_common+0x4c/0xb0\n  nvmem_cell_read_variable_le_u32+0x40/0x100\n  a6xx_gpu_init+0x170/0x2f4\n  adreno_bind+0x174/0x284\n  component_bind_all+0xf0/0x264\n  msm_drm_bind+0x1d8/0x7a0\n  try_to_bring_up_master+0x164/0x1ac\n  __component_add+0xbc/0x13c\n  component_add+0x20/0x2c\n  dp_display_probe+0x340/0x384\n  platform_probe+0xc0/0x100\n  really_probe+0x110/0x304\n  __driver_probe_device+0xb8/0x120\n  driver_probe_device+0x4c/0xfc\n  __device_attach_driver+0xb0/0x128\n  bus_for_each_drv+0x90/0xdc\n  __device_attach+0xc8/0x174\n  device_initial_probe+0x20/0x2c\n  bus_probe_device+0x40/0xa4\n  deferred_probe_work_func+0x7c/0xb8\n  process_one_work+0x128/0x21c\n  process_scheduled_works+0x40/0x54\n  worker_thread+0x1ec/0x2a8\n  kthread+0x138/0x158\n  ret_from_fork+0x10/0x20\n\nFix it by making sure there are any bits to mask out.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":["CWE-787"],"references":["https://git.kernel.org/stable/c/0594f1d048d8dc338eb9a240021b1d00ae1eb082","https://git.kernel.org/stable/c/0e822e5413da1af28cca350cb1cb42b6133bdcae","https://git.kernel.org/stable/c/2df6c023050205c4d04ffc121bc549f65cb8d1df","https://git.kernel.org/stable/c/57e48886401b14cd351423fabfec2cfd18df4f66","https://git.kernel.org/stable/c/5d388fa01fa6eb310ac023a363a6cb216d9d8fe9"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:50:30.954589733+00:00"},"epss":{"cve":"CVE-2021-47497","score":0.00221,"percentile":0.12748,"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."]}