{"cve":"CVE-2022-48943","nvd":{"published":"2024-08-22T04:15:19.027","modified":"2026-08-04T10:17:27.647","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: x86/mmu: make apf token non-zero to fix bug\n\nIn current async pagefault logic, when a page is ready, KVM relies on\nkvm_arch_can_dequeue_async_page_present() to determine whether to deliver\na READY event to the Guest. This function test token value of struct\nkvm_vcpu_pv_apf_data, which must be reset to zero by Guest kernel when a\nREADY event is finished by Guest. If value is zero meaning that a READY\nevent is done, so the KVM can deliver another.\nBut the kvm_arch_setup_async_pf() may produce a valid token with zero\nvalue, which is confused with previous mention and may lead the loss of\nthis READY event.\n\nThis bug may cause task blocked forever in Guest:\n INFO: task stress:7532 blocked for more than 1254 seconds.\n       Not tainted 5.10.0 #16\n \"echo 0 > /proc/sys/kernel/hung_task_timeout_secs\" disables this message.\n task:stress          state:D stack:    0 pid: 7532 ppid:  1409\n flags:0x00000080\n Call Trace:\n  __schedule+0x1e7/0x650\n  schedule+0x46/0xb0\n  kvm_async_pf_task_wait_schedule+0xad/0xe0\n  ? exit_to_user_mode_prepare+0x60/0x70\n  __kvm_handle_async_pf+0x4f/0xb0\n  ? asm_exc_page_fault+0x8/0x30\n  exc_page_fault+0x6f/0x110\n  ? asm_exc_page_fault+0x8/0x30\n  asm_exc_page_fault+0x1e/0x30\n RIP: 0033:0x402d00\n RSP: 002b:00007ffd31912500 EFLAGS: 00010206\n RAX: 0000000000071000 RBX: ffffffffffffffff RCX: 00000000021a32b0\n RDX: 000000000007d011 RSI: 000000000007d000 RDI: 00000000021262b0\n RBP: 00000000021262b0 R08: 0000000000000003 R09: 0000000000000086\n R10: 00000000000000eb R11: 00007fefbdf2baa0 R12: 0000000000000000\n R13: 0000000000000002 R14: 000000000007d000 R15: 0000000000001000","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":[],"references":["https://git.kernel.org/stable/c/4c3644b6c96c5daa5149e5abddc07234eea47c7c","https://git.kernel.org/stable/c/62040f5cd7d937de547836e747b6aa8212fec573","https://git.kernel.org/stable/c/6f3c1fc53d86d580d8d6d749c4af23705e4f6f79","https://git.kernel.org/stable/c/72fdfc75d4217b32363cc80def3de2cb3fef3f02"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:54:16.205165117+00:00"},"epss":{"cve":"CVE-2022-48943","score":0.00247,"percentile":0.16084,"date":"2026-10-31"},"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."]}