CVE & CISA-KEV Catalog

CVE-2016-4020

MEDIUM
6.5
CVSS v3
NVD

Description

The patch_instruction function in hw/i386/kvmvapic.c in QEMU does not initialize the imm32 variable, which allows local guest OS administrators to obtain sensitive information from host stack memory by accessing the Task Priority Register (TPR).

How to fix

Remediation Available
qemuDebian
Fixed in:1:2.6+dfsg-2CVE-2016-4020
Fixed in:1:2.6+dfsg-2CVE-2016-4020
Fixed in:1:2.6+dfsg-2CVE-2016-4020
Fixed in:1:2.6+dfsg-2CVE-2016-4020
qemuUbuntu
Fixed in:2.0.0+dfsg-2ubuntu1.24USN-2974-1
Fixed in:1:2.5+dfsg-5ubuntu10.1USN-2974-1
qemu-systemUbuntu
Fixed in:2.0.0+dfsg-2ubuntu1.24USN-2974-1
Fixed in:1:2.5+dfsg-5ubuntu10.1USN-2974-1
qemu-system-aarch64Ubuntu
Fixed in:2.0.0+dfsg-2ubuntu1.24USN-2974-1
Fixed in:1:2.5+dfsg-5ubuntu10.1USN-2974-1
qemu-system-armUbuntu
Fixed in:2.0.0+dfsg-2ubuntu1.24USN-2974-1
Fixed in:1:2.5+dfsg-5ubuntu10.1USN-2974-1
qemu-system-mipsUbuntu
Fixed in:2.0.0+dfsg-2ubuntu1.24USN-2974-1
Fixed in:1:2.5+dfsg-5ubuntu10.1USN-2974-1
qemu-system-miscUbuntu
Fixed in:2.0.0+dfsg-2ubuntu1.24USN-2974-1
Fixed in:1:2.5+dfsg-5ubuntu10.1USN-2974-1
qemu-system-ppcUbuntu
Fixed in:2.0.0+dfsg-2ubuntu1.24USN-2974-1
Fixed in:1:2.5+dfsg-5ubuntu10.1USN-2974-1
qemu-system-s390xUbuntu
Fixed in:1:2.5+dfsg-5ubuntu10.1USN-2974-1
qemu-system-sparcUbuntu
Fixed in:2.0.0+dfsg-2ubuntu1.24USN-2974-1
Fixed in:1:2.5+dfsg-5ubuntu10.1USN-2974-1
qemu-system-x86Ubuntu
Fixed in:2.0.0+dfsg-2ubuntu1.24USN-2974-1
Fixed in:1:2.5+dfsg-5ubuntu10.1USN-2974-1

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorLocal
Attack ComplexityLow
Privileges RequiredLow
User InteractionNone
ScopeChanged

Impact

ConfidentialityHigh
IntegrityNone
AvailabilityNone

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

Exploit Intelligence

0.37%probability of exploitation in 30 days
29thpercentile

Low risk: more likely to be exploited than 29% of all known CVEs.

References

Other references1
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Markdown

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HTML

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-06.