PT-2021-7719 · Qemu+9 · Qemu+9

Alexander Bulekov + 1 · Published 2021-04-19 · Updated 2026-06-09 · CVE-2021-3507

Positive Technologies (AI Summary)

CVSS v3.1

6.1

Medium

Base vector

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

Name of the Vulnerable Software and Affected Versions QEMU versions up to 6.0.0

Description A heap buffer overflow was found in the floppy disk emulator of QEMU. It could occur in fdctrl transfer handler() in hw/block/fdc.c while processing DMA read data transfers from the floppy drive to the guest system. A privileged guest user could use this flaw to crash the QEMU process on the host, resulting in a denial-of-service scenario, or potential information leakage from the host memory.

Recommendations For QEMU versions up to 6.0.0, as a temporary workaround, consider disabling the fdctrl transfer handler() function until a patch is available. Restrict access to the hw/block/fdc.c component to minimize the risk of exploitation. Avoid using the floppy disk emulator until the issue is resolved. At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Exploit

DoS

Memory Corruption

Buffer Overflow

Weakness Enumeration

CWE-787

CWE-119

Related Identifiers

ALSA-2022:7967

ALT-PU-2021-2713

ALT-PU-2021-3363

ALT-PU-2022-2009

ALT-PU-2022-3081

ALT-PU-2022-3390

ALT-PU-2023-1830

ALT-PU-2023-1869

BDU:2023-01705

CESA-2022_7472

CVE-2021-3507

DLA-3099-1

OESA-2022-1716

OPENSUSE-SU-2022_3768-1

RHSA-2022:7472

RHSA-2022:7967

RHSA-2022_7472

RHSA-2022_7967

RLSA-2022:7472

RLSA-2022:7967

SUSE-SU-2022:3768-1

SUSE-SU-2023:0761-1

SUSE-SU-2023:0840-1

SUSE-SU-2023:0878-1

SUSE-SU-2023:0879-1

SUSE-SU-2023:0879-2

SUSE-SU-2023_0878-1

USN-5489-1

USN-8412-1

Affected Products

Alt Linux

Almalinux

Astra Linux

Centos

Linuxmint

Qemu

Red Hat

Rocky Linux

Suse

Ubuntu

References · 224

• 🔥 https://github.com/QiuhaoLi/CVE-2021-3929-3947 · Exploit
• 🔥 https://bugzilla.redhat.com/show_bug.cgi?id=1951118 · Exploit
• https://ubuntu.com/security/CVE-2021-4206 · Vendor Advisory
• https://ubuntu.com/security/CVE-2020-15863 · Vendor Advisory
• https://ubuntu.com/security/CVE-2020-15469 · Vendor Advisory
• https://osv.dev/vulnerability/USN-8412-1 · Vendor Advisory
• https://osv.dev/vulnerability/RLSA-2022:7472 · Vendor Advisory
• https://cve.org/CVERecord?id=CVE-2021-3507 · Security Note
• https://ubuntu.com/security/CVE-2021-20221 · Vendor Advisory
• https://osv.dev/vulnerability/USN-5489-1 · Vendor Advisory
• https://ubuntu.com/security/CVE-2021-4207 · Vendor Advisory
• https://osv.dev/vulnerability/OESA-2022-1716 · Vendor Advisory
• https://ubuntu.com/security/CVE-2020-11947 · Vendor Advisory
• https://ubuntu.com/security/CVE-2023-3354 · Vendor Advisory
• https://security-tracker.debian.org/tracker/CVE-2021-3507 · Vendor Advisory