CVE-2022-48943
KVM: x86/mmu: make apf token non-zero to fix bug
- Published
- Updated
- Reserved
- Assigned by
- Linux
Description
In the Linux kernel, the following vulnerability has been resolved: KVM: x86/mmu: make apf token non-zero to fix bug In current async pagefault logic, when a page is ready, KVM relies on kvm_arch_can_dequeue_async_page_present() to determine whether to deliver a READY event to the Guest. This function test token value of struct kvm_vcpu_pv_apf_data, which must be reset to zero by Guest kernel when a READY event is finished by Guest. If value is zero meaning that a READY event is done, so the KVM can deliver another. But the kvm_arch_setup_async_pf() may produce a valid token with zero value, which is confused with previous mention and may lead the loss of this READY event. This bug may cause task blocked forever in Guest: INFO: task stress:7532 blocked for more than 1254 seconds. Not tainted 5.10.0 #16 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:stress state:D stack: 0 pid: 7532 ppid: 1409 flags:0x00000080 Call Trace: __schedule+0x1e7/0x650 schedule+0x46/0xb0 kvm_async_pf_task_wait_schedule+0xad/0xe0 ? exit_to_user_mode_prepare+0x60/0x70 __kvm_handle_async_pf+0x4f/0xb0 ? asm_exc_page_fault+0x8/0x30 exc_page_fault+0x6f/0x110 ? asm_exc_page_fault+0x8/0x30 asm_exc_page_fault+0x1e/0x30 RIP: 0033:0x402d00 RSP: 002b:00007ffd31912500 EFLAGS: 00010206 RAX: 0000000000071000 RBX: ffffffffffffffff RCX: 00000000021a32b0 RDX: 000000000007d011 RSI: 000000000007d000 RDI: 00000000021262b0 RBP: 00000000021262b0 R08: 0000000000000003 R09: 0000000000000086 R10: 00000000000000eb R11: 00007fefbdf2baa0 R12: 0000000000000000 R13: 0000000000000002 R14: 000000000007d000 R15: 0000000000001000
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | High7.1 | CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H |
| NVDNVD · Modified | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.25% · top 84% of all CVEs (6 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.1.
Affected products
- affected 2635b5c4a0e407b84f68e188c719f28ba0e9ae1b – < 72fdfc75d4217b32363cc80def3de2cb3fef3f02
- affected 2635b5c4a0e407b84f68e188c719f28ba0e9ae1b – < 4c3644b6c96c5daa5149e5abddc07234eea47c7c
- affected 2635b5c4a0e407b84f68e188c719f28ba0e9ae1b – < 62040f5cd7d937de547836e747b6aa8212fec573
- affected 2635b5c4a0e407b84f68e188c719f28ba0e9ae1b – < 6f3c1fc53d86d580d8d6d749c4af23705e4f6f79
- affected 5.8
- unaffected < 5.8
- unaffected 5.10.103 – ≤ 5.10.*
- unaffected 5.15.26 – ≤ 5.15.*
- unaffected 5.16.12 – ≤ 5.16.*
- unaffected 5.17 – ≤ *
References (4)
- https://git.kernel.org/stable/c/72fdfc75d4217b32363cc80def3de2cb3fef3f02 (opens in a new tab)
- https://git.kernel.org/stable/c/4c3644b6c96c5daa5149e5abddc07234eea47c7c (opens in a new tab)
- https://git.kernel.org/stable/c/62040f5cd7d937de547836e747b6aa8212fec573 (opens in a new tab)
- https://git.kernel.org/stable/c/6f3c1fc53d86d580d8d6d749c4af23705e4f6f79 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2022-48943)Record last updated .