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CVE-2022-48943· NVD / CVE Program· CNA Linux

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

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

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Aug 22, 2024
Updated
Aug 5, 2026
EPSS
0.2% · 14th percentile
CWE
—
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JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
7.8
CNA · Linux
7.1
0.7 point gap

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Affected systems

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernelbefore 5.10.103
  • linux linux kernel5.11 and later · before 5.15.26
  • linux linux kernel5.16 and later · before 5.16.12

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 5.8affected
    • 2635b5c4a0e407b84f68e188c719f28ba0e9ae1b and later · before 72fdfc75d4217b32363cc80def3de2cb3fef3f02affected · git
    • 2635b5c4a0e407b84f68e188c719f28ba0e9ae1b and later · before 4c3644b6c96c5daa5149e5abddc07234eea47c7caffected · git
    • 2635b5c4a0e407b84f68e188c719f28ba0e9ae1b and later · before 62040f5cd7d937de547836e747b6aa8212fec573affected · git
    • 2635b5c4a0e407b84f68e188c719f28ba0e9ae1b and later · before 6f3c1fc53d86d580d8d6d749c4af23705e4f6f79affected · git
    • before 5.8not affected · semver
    • 5.10.103 and later · up to and including 5.10.*not affected · semver
    • 5.15.26 and later · up to and including 5.15.*not affected · semver
    • 5.16.12 and later · up to and including 5.16.*not affected · semver
    • 5.17 and laternot affected · original_commit_for_fix

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 5.16.12-15.16.12-1
Red Hat:enterprise_linux:8::baseosbpftoolbefore 0:4.18.0-372.26.1.el8_60:4.18.0-372.26.1.el8_6
Red Hat:enterprise_linux:8::baseoskernelbefore 0:4.18.0-372.26.1.el8_60:4.18.0-372.26.1.el8_6
Red Hat:enterprise_linux:8::baseoskernel-abi-stablelistsbefore 0:4.18.0-372.26.1.el8_60:4.18.0-372.26.1.el8_6
Red Hat:enterprise_linux:8::baseoskernel-corebefore 0:4.18.0-372.26.1.el8_60:4.18.0-372.26.1.el8_6
Red Hat:enterprise_linux:8::baseoskernel-debugbefore 0:4.18.0-372.26.1.el8_60:4.18.0-372.26.1.el8_6
Red Hat:enterprise_linux:8::baseoskernel-debug-corebefore 0:4.18.0-372.26.1.el8_60:4.18.0-372.26.1.el8_6
Red Hat:enterprise_linux:8::baseoskernel-debug-develbefore 0:4.18.0-372.26.1.el8_60:4.18.0-372.26.1.el8_6
Red Hat:enterprise_linux:8::baseoskernel-debug-modulesbefore 0:4.18.0-372.26.1.el8_60:4.18.0-372.26.1.el8_6
Red Hat:enterprise_linux:8::baseoskernel-debug-modules-extrabefore 0:4.18.0-372.26.1.el8_60:4.18.0-372.26.1.el8_6
Red Hat:enterprise_linux:8::baseoskernel-debuginfo-common-aarch64before 0:4.18.0-372.26.1.el8_60:4.18.0-372.26.1.el8_6
Red Hat:enterprise_linux:8::baseoskernel-debuginfo-common-ppc64lebefore 0:4.18.0-372.26.1.el8_60:4.18.0-372.26.1.el8_6
Red Hat:enterprise_linux:8::baseoskernel-debuginfo-common-s390xbefore 0:4.18.0-372.26.1.el8_60:4.18.0-372.26.1.el8_6
Red Hat:enterprise_linux:8::baseoskernel-docbefore 0:4.18.0-372.26.1.el8_60:4.18.0-372.26.1.el8_6
Red Hat:enterprise_linux:8::baseoskernel-modulesbefore 0:4.18.0-372.26.1.el8_60:4.18.0-372.26.1.el8_6
Red Hat:enterprise_linux:8::baseoskernel-modules-extrabefore 0:4.18.0-372.26.1.el8_60:4.18.0-372.26.1.el8_6
Red Hat:enterprise_linux:8::baseoskernel-toolsbefore 0:4.18.0-372.26.1.el8_60:4.18.0-372.26.1.el8_6
Red Hat:enterprise_linux:8::baseoskernel-tools-libsbefore 0:4.18.0-372.26.1.el8_60:4.18.0-372.26.1.el8_6
Red Hat:enterprise_linux:8::baseoskernel-zfcpdumpbefore 0:4.18.0-372.26.1.el8_60:4.18.0-372.26.1.el8_6
Red Hat:enterprise_linux:8::baseoskernel-zfcpdump-corebefore 0:4.18.0-372.26.1.el8_60:4.18.0-372.26.1.el8_6
Red Hat:enterprise_linux:8::baseoskernel-zfcpdump-debuginfobefore 0:4.18.0-372.26.1.el8_60:4.18.0-372.26.1.el8_6
Red Hat:enterprise_linux:8::baseoskernel-zfcpdump-develbefore 0:4.18.0-372.26.1.el8_60:4.18.0-372.26.1.el8_6
Red Hat:enterprise_linux:8::baseoskernel-zfcpdump-modulesbefore 0:4.18.0-372.26.1.el8_60:4.18.0-372.26.1.el8_6
Red Hat:enterprise_linux:8::baseoskernel-zfcpdump-modules-extrabefore 0:4.18.0-372.26.1.el8_60:4.18.0-372.26.1.el8_6

+61

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Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux4c3644b6c96c5daa5149e5abddc07234eea47c7cVendor (CNA)
Linux Linux62040f5cd7d937de547836e747b6aa8212fec573Vendor (CNA)
Linux Linux6f3c1fc53d86d580d8d6d749c4af23705e4f6f79Vendor (CNA)
Linux Linux72fdfc75d4217b32363cc80def3de2cb3fef3f02Vendor (CNA)
debian:linux5.16.12-1 · Debian:12Package registry (OSV)
red hat:bpftool-debuginfo0:5.14.0-70.22.1.el9_0 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-debug-debuginfo0:5.14.0-70.22.1.el9_0 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-debug-devel0:5.14.0-70.22.1.el9_0 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-debug-devel-matched0:5.14.0-70.22.1.el9_0 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-debuginfo0:5.14.0-70.22.1.el9_0 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-debuginfo-common-aarch640:5.14.0-70.22.1.el9_0 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-debuginfo-common-ppc64le0:5.14.0-70.22.1.el9_0 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-debuginfo-common-s390x0:5.14.0-70.22.1.el9_0 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-debuginfo-common-x86_640:5.14.0-70.22.1.el9_0 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-devel0:5.14.0-70.22.1.el9_0 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-devel-matched0:5.14.0-70.22.1.el9_0 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-doc0:5.14.0-70.22.1.el9_0 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
suse:kernel-azure4.12.14-16.200.1 · SUSE:Linux Enterprise Server 12 SP5Package registry (OSV)
suse:kernel-default4.12.14-122.231.1 · SUSE:Linux Enterprise High Availability Extension 12 SP5Package registry (OSV)
suse:kernel-docs4.12.14-122.231.1 · SUSE:Linux Enterprise Software Development Kit 12 SP5Package registry (OSV)
suse:kernel-obs-build4.12.14-122.231.1 · SUSE:Linux Enterprise Software Development Kit 12 SP5Package registry (OSV)
suse:kernel-rt4.12.14-10.203.1 · SUSE:Linux Enterprise Real Time 12 SP5Package registry (OSV)
suse:kernel-rt_debug4.12.14-10.203.1 · SUSE:Linux Enterprise Real Time 12 SP5Package registry (OSV)
suse:kernel-source4.12.14-122.231.1 · SUSE:Linux Enterprise Server 12 SP5Package registry (OSV)
suse:kernel-source-azure4.12.14-16.200.1 · SUSE:Linux Enterprise Server 12 SP5Package registry (OSV)
suse:kernel-source-rt4.12.14-10.203.1 · SUSE:Linux Enterprise Real Time 12 SP5Package registry (OSV)
suse:kernel-syms4.12.14-122.231.1 · SUSE:Linux Enterprise Server 12 SP5Package registry (OSV)
suse:kernel-syms-rt4.12.14-10.203.1 · SUSE:Linux Enterprise Real Time 12 SP5Package registry (OSV)
suse:kgraft-patch-SLE12-SP5_Update_611-8.3.1 · SUSE:Linux Enterprise Live Patching 12 SP5Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

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Change log

  1. Fix✗ → ✓

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References

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