CVE-2020-35517

Guest-to-host escape via unchecked special-file opens

Published Jan 28, 2021 · Updated Aug 4, 2024

Improper privilege management in QEMU Project QEMU 5.2.0 virtiofsd allows privileged guest OS users to access host devices through virtio-fs. FUSE_OPEN and related paths open device nodes without first checking the inode type, so a malicious guest driver makes the daemon operate on host special files. Exploitation requires a privileged guest OS user, a modified guest device driver, and a virtio-fs share; the resulting host-file read and write access breaches guest isolation.

CVSS severity7.5
High
EPSS probability0.52%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper privilege management in QEMU Project QEMU 5.2.0 virtiofsd allows privileged guest OS users to access host devices through virtio-fs. FUSE_OPEN and related paths open device nodes without first checking the inode type, so a malicious guest driver makes the daemon operate on host special files. Exploitation requires a privileged guest OS user, a modified guest device driver, and a virtio-fs share; the resulting host-file read and write access breaches guest isolation.

The record

CVE
CVE-2020-35517
Published
Jan 28, 2021
Updated
Aug 4, 2024
Vendor
QEMU Project
Product
QEMU
Classifications
CWE-269, T1068
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Jan 28, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=qemu 5.2.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

QEMU Project · QEMUversion=qemu 5.2.0

Published CVSS scores

7.5Red Hat, Inc.CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H
8.2NISTCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-269Improper Privilege Management
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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