CVE-2021-20255

Name: CVE-2021-20255
Creator: NVD / NIST
Published: 2021-03-09T20:15:13.133+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.5/10EPSS 0.41%

Last modified Jun 17, 2026

CVE-2021-20255 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. A stack overflow via an infinite recursion vulnerability was found in the eepro100 i8255x device emulator of QEMU. This issue occurs while processing controller commands due to a DMA reentry issue. EPSS estimates a 0.41% chance of exploitation in the next 30 days.

Description

A stack overflow via an infinite recursion vulnerability was found in the eepro100 i8255x device emulator of QEMU. This issue occurs while processing controller commands due to a DMA reentry issue. This flaw allows a guest user or process to consume CPU cycles or crash the QEMU process on the host, resulting in a denial of service. The highest threat from this vulnerability is to system availability.

Metrics

CVSS 3.1

5.5/10

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

EPSS Probability

0.41%

32.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Qemu	Qemu	All versions
Debian	Debian Linux	9.0

References

https://bugzilla.redhat.com/show_bug.cgi?id=1930646Issue Tracking, Patch, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/04/msg00009.htmlMailing List, Third Party Advisory
https://ruhr-uni-bochum.sciebo.de/s/NNWP2GfwzYKeKwE?path=%2Feepro100_stackoverflow1Third Party Advisory
https://security.netapp.com/advisory/ntap-20210507-0003/Third Party Advisory
https://www.openwall.com/lists/oss-security/2021/02/25/1Mailing List, Patch, Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1930646Issue Tracking, Patch, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/04/msg00009.htmlMailing List, Third Party Advisory
https://ruhr-uni-bochum.sciebo.de/s/NNWP2GfwzYKeKwE?path=%2Feepro100_stackoverflow1Third Party Advisory
https://security.netapp.com/advisory/ntap-20210507-0003/Third Party Advisory
https://www.openwall.com/lists/oss-security/2021/02/25/1Mailing List, Patch, Third Party Advisory

Timeline

Published: Mar 9, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-20255?

How severe is CVE-2021-20255?

CVE-2021-20255 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.41% probability of exploitation in the next 30 days.

How do I fix CVE-2021-20255?

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-2021-20255?

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

Scan your code now

Source: NVD / NIST