🛡️ CVE-2021-3750 on Debian — qemu

⚪ Unknown ✅ No Known Exploit OSV

N/A

CVSS Score

0 Low4 Medium7 High9 Critical10

Description

A DMA reentrancy issue was found in the USB EHCI controller emulation of QEMU. EHCI does not verify if the Buffer Pointer overlaps with its MMIO region when it transfers the USB packets. Crafted content may be written to the controller's registers and trigger undesirable actions (such as reset) while the device is still transferring packets. This can ultimately lead to a use-after-free issue. A malicious guest could use this flaw to crash the QEMU process on the host, resulting in a denial of service condition, or potentially execute arbitrary code within the context of the QEMU process on the host. This flaw affects QEMU versions before 7.0.0.

Distribution advisory

This page covers CVE-2021-3750 as tracked by Debian, for the package qemu. The fix is available in version 1:7.0+dfsg-1; earlier versions remain affected.

How this vulnerability can be exploited

This issue can be reached with local access to the system, attack complexity is low, an attacker needs administrative privileges on the target. No user interaction is required. The scope is changed, meaning a successful attack can affect components beyond the vulnerable one. Rated impact: confidentiality high, integrity high, availability high.

Affected software

DEBIAN-CVE-2021-3750 is recorded against 1 package.

qemu (fixed in 1:7.0+dfsg-1)

Timeline and source

Published on 2 May 2022 and last revised on 4 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

security-tracker.debian.org (Advisory)

CVE-2021-3750 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Ubuntu

Details

Severity Unknown

CVSS Score N/A

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

CWE N/A

Public Exploit ✅ No

Source OSV

Published 2022-05-02

Updated 2026-08-20

Modified 2026-08-04

Fix URL N/A

Affected Packages

Software	From version	Fixed in
qemu	—	1:7.0+dfsg-1

References

ADVISORY https://security-tracker.debian.org/tracker/CVE-2021-3750

🔗 NVD 🔗 Mitre

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