CVE-2021-3507

Name: CVE-2021-3507
Creator: NVD / NIST
Published: 2021-05-06T16:15:07.547+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.1/10EPSS 0.48%

Last modified Jun 17, 2026

CVE-2021-3507 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. A heap buffer overflow was found in the floppy disk emulator of QEMU up to 6.0.0 (including). 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. EPSS estimates a 0.48% chance of exploitation in the next 30 days.

Description

A heap buffer overflow was found in the floppy disk emulator of QEMU up to 6.0.0 (including). 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 DoS scenario, or potential information leakage from the host memory.

Metrics

CVSS 3.1

6.1/10

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

EPSS Probability

0.48%

38.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Qemu	Qemu	<= 6.0.0
Debian	Debian Linux	10.0
Redhat	Enterprise Linux	8.0

References

https://bugzilla.redhat.com/show_bug.cgi?id=1951118Exploit, Issue Tracking, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/09/msg00008.htmlMailing List, Third Party Advisory
https://security.netapp.com/advisory/ntap-20210528-0005/Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1951118Exploit, Issue Tracking, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/09/msg00008.htmlMailing List, Third Party Advisory
https://security.netapp.com/advisory/ntap-20210528-0005/Third Party Advisory

Timeline

Published: May 6, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-3507?

How severe is CVE-2021-3507?

CVE-2021-3507 has a CVSS score of 6.1/10 (MEDIUM severity). The EPSS model estimates a 0.48% probability of exploitation in the next 30 days.

How do I fix CVE-2021-3507?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-3507?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST