{"cve":"CVE-2021-47217","nvd":{"published":"2024-04-10T19:15:48.813","modified":"2026-06-17T04:16:55.890","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nx86/hyperv: Fix NULL deref in set_hv_tscchange_cb() if Hyper-V setup fails\n\nCheck for a valid hv_vp_index array prior to derefencing hv_vp_index when\nsetting Hyper-V's TSC change callback.  If Hyper-V setup failed in\nhyperv_init(), the kernel will still report that it's running under\nHyper-V, but will have silently disabled nearly all functionality.\n\n  BUG: kernel NULL pointer dereference, address: 0000000000000010\n  #PF: supervisor read access in kernel mode\n  #PF: error_code(0x0000) - not-present page\n  PGD 0 P4D 0\n  Oops: 0000 [#1] SMP\n  CPU: 4 PID: 1 Comm: swapper/0 Not tainted 5.15.0-rc2+ #75\n  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015\n  RIP: 0010:set_hv_tscchange_cb+0x15/0xa0\n  Code: <8b> 04 82 8b 15 12 17 85 01 48 c1 e0 20 48 0d ee 00 01 00 f6 c6 08\n  ...\n  Call Trace:\n   kvm_arch_init+0x17c/0x280\n   kvm_init+0x31/0x330\n   vmx_init+0xba/0x13a\n   do_one_initcall+0x41/0x1c0\n   kernel_init_freeable+0x1f2/0x23b\n   kernel_init+0x16/0x120\n   ret_from_fork+0x22/0x30","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-476"],"references":["https://git.kernel.org/stable/c/8823ea27fff6084bbb4bc71d15378fae0220b1d8","https://git.kernel.org/stable/c/9c177eee116cf888276d3748cb176e72562cfd5c","https://git.kernel.org/stable/c/b0e44dfb4e4c699cca33ede431b8d127e6e8d661","https://git.kernel.org/stable/c/b20ec58f8a6f4fef32cc71480ddf824584e24743","https://git.kernel.org/stable/c/daf972118c517b91f74ff1731417feb4270625a4"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:48:32.179249784+00:00"},"epss":{"cve":"CVE-2021-47217","score":0.00235,"percentile":0.14548,"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."]}