CVE-2021-20257

Name: CVE-2021-20257
Creator: NVD / NIST
Published: 2022-03-16T15:15:09.983+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 0.36%

Last modified Jun 17, 2026

CVE-2021-20257 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. An infinite loop flaw was found in the e1000 NIC emulator of the QEMU. This issue occurs while processing transmits (tx) descriptors in process_tx_desc if various descriptor fields are initialized with invalid values. EPSS estimates a 0.36% chance of exploitation in the next 30 days.

Description

An infinite loop flaw was found in the e1000 NIC emulator of the QEMU. This issue occurs while processing transmits (tx) descriptors in process_tx_desc if various descriptor fields are initialized with invalid values. This flaw allows a guest to consume CPU cycles on the host, resulting in a denial of service. The highest threat from this vulnerability is to system availability.

Metrics

CVSS 3.1

6.5/10

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

EPSS Probability

0.36%

27.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Qemu	Qemu	< 6.2.0
Fedoraproject	Fedora	33
Redhat	Openstack Platform	10.0
Redhat	Openstack Platform	13.0
Redhat	Enterprise Linux	6.0
Redhat	Enterprise Linux	8.0
Redhat	Enterprise Linux For Ibm Z Systems	8.0
Redhat	Enterprise Linux For Power Little Endian	8.0
Redhat	Codeready Linux Builder	All versions
Debian	Debian Linux	10.0

References

https://bugzilla.redhat.com/show_bug.cgi?id=1930087Issue Tracking, Patch, Third Party Advisory
https://github.com/qemu/qemu/commit/3de46e6fc489c52c9431a8a832ad8170a7569bd8Patch, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/09/msg00008.htmlMailing List, Third Party Advisory
https://lists.gnu.org/archive/html/qemu-devel/2021-02/msg07428.htmlMailing List, Patch, Vendor Advisory
https://security.gentoo.org/glsa/202208-27Third Party Advisory
https://security.netapp.com/advisory/ntap-20220425-0003/Third Party Advisory
https://www.openwall.com/lists/oss-security/2021/02/25/2Mailing List, Patch, Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1930087Issue Tracking, Patch, Third Party Advisory
https://github.com/qemu/qemu/commit/3de46e6fc489c52c9431a8a832ad8170a7569bd8Patch, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/09/msg00008.htmlMailing List, Third Party Advisory
https://lists.gnu.org/archive/html/qemu-devel/2021-02/msg07428.htmlMailing List, Patch, Vendor Advisory
https://security.gentoo.org/glsa/202208-27Third Party Advisory
https://security.netapp.com/advisory/ntap-20220425-0003/Third Party Advisory
https://www.openwall.com/lists/oss-security/2021/02/25/2Mailing List, Patch, Third Party Advisory

Timeline

Published: Mar 16, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-20257?

How severe is CVE-2021-20257?

CVE-2021-20257 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.36% probability of exploitation in the next 30 days.

How do I fix CVE-2021-20257?

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-2021-20257?

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

Scan your code now

Source: NVD / NIST