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Vulnerability · Published Aug 22, 2024 · Assigned by Linux

CVE-2022-48943KVM: x86/mmu: make apf token non-zero to fix bug

High 7.1

In plain English

A high-severity security flaw in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 16% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.1High
Exploit odds (30 days)0.2%top 83.9% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux5.16.12-1DEBIAN-CVE-2022-48943
Debian:13linux5.16.12-1DEBIAN-CVE-2022-48943
Debian:14linux5.16.12-1DEBIAN-CVE-2022-48943
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2022-48943
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2022-48943
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2022-48943
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2022-48943
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2022-48943
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2022-48943
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2022-48943
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2022-48943
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2022-48943
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2022-48943
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2022-48943
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2022-48943
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2022-48943
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2022-48943
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2022-48943
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2022-48943
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2022-48943
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2022-48943
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2022-48943
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2022-48943
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2022-48943
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2022-48943
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2022-48943
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2022-48943
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2022-48943
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2022-48943
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2022-48943
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2022-48943
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2022-48943
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2022-48943
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2022-48943
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2022-48943
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2022-48943

Affected products (as reported)

VendorProductVersions
Linux Linux 2635b5c4a0e407b84f68e188c719f28ba0e9ae1b – before 72fdfc75d4217b32363cc80def3de2cb3fef3f022635b5c4a0e407b84f68e188c719f28ba0e9ae1b – before 4c3644b6c96c5daa5149e5abddc07234eea47c7c2635b5c4a0e407b84f68e188c719f28ba0e9ae1b – before 62040f5cd7d937de547836e747b6aa8212fec5732635b5c4a0e407b84f68e188c719f28ba0e9ae1b – before 6f3c1fc53d86d580d8d6d749c4af23705e4f6f79
Linux Linux 5.8

References