CVE-2021-3545

Host-memory disclosure via uninitialized capset response

Published Jun 2, 2021 · Updated Aug 3, 2024

Information disclosure in QEMU 6.0 and earlier allows guest OS users to read host memory through the vhost-user GPU device. The virgl_cmd_get_capset_info() handler returns a partially filled response structure without first clearing it, exposing residual host-process bytes to the guest. Exploitation requires a guest able to query a virgl-enabled vhost-user-gpu backend; the demonstrated consequence is host-memory disclosure.

CVSS severity6.5
Medium
EPSS probability0.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in QEMU 6.0 and earlier allows guest OS users to read host memory through the vhost-user GPU device. The virgl_cmd_get_capset_info() handler returns a partially filled response structure without first clearing it, exposing residual host-process bytes to the guest. Exploitation requires a guest able to query a virgl-enabled vhost-user-gpu backend; the demonstrated consequence is host-memory disclosure.

The record

CVE
CVE-2021-3545
Published
Jun 2, 2021
Updated
Aug 3, 2024
Vendor
QEMU Project
Product
QEMU
Classifications
CWE-908, T1005
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 2, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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=All QEMU versions up to and including 6.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

QEMU Project · QEMUversion=All QEMU versions up to and including 6.0

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-908Use of Uninitialized Resource
T1005Data from Local System

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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