CVE-2021-3593

Name: CVE-2021-3593
Creator: NVD / NIST
Published: 2021-06-15T21:15:09.677+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

LOWCVSS 3.8/10EPSS 0.33%

Last modified Jun 17, 2026

CVE-2021-3593 is a low-severity vulnerability rated 3.8/10 on the CVSS scale. An invalid pointer initialization issue was found in the SLiRP networking implementation of QEMU. The flaw exists in the udp6_input() function and could occur while processing a udp packet that is smaller than the size of the 'udphdr' structure. EPSS estimates a 0.33% chance of exploitation in the next 30 days.

Description

An invalid pointer initialization issue was found in the SLiRP networking implementation of QEMU. The flaw exists in the udp6_input() function and could occur while processing a udp packet that is smaller than the size of the 'udphdr' structure. This issue may lead to out-of-bounds read access or indirect host memory disclosure to the guest. The highest threat from this vulnerability is to data confidentiality. This flaw affects libslirp versions prior to 4.6.0.

Metrics

CVSS 3.1

3.8/10

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

EPSS Probability

0.33%

24.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Libslirp Project	Libslirp	< 4.6.0
Redhat	Enterprise Linux	8.0
Fedoraproject	Fedora	33
Fedoraproject	Fedora	34
Debian	Debian Linux	9.0

References

https://bugzilla.redhat.com/show_bug.cgi?id=1970487Issue Tracking, Patch, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/04/msg00002.htmlMailing List, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2023/03/msg00013.html
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GCKWZWY64EHTOQMLVLTSZ4AA27EWRJMH/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SGPQZFVJCFGDSISFXPCQTTBBD7QZLJKI/
https://security.gentoo.org/glsa/202107-44Third Party Advisory
https://security.netapp.com/advisory/ntap-20210805-0004/Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1970487Issue Tracking, Patch, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/04/msg00002.htmlMailing List, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2023/03/msg00013.html
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GCKWZWY64EHTOQMLVLTSZ4AA27EWRJMH/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SGPQZFVJCFGDSISFXPCQTTBBD7QZLJKI/
https://security.gentoo.org/glsa/202107-44Third Party Advisory
https://security.netapp.com/advisory/ntap-20210805-0004/Third Party Advisory

Timeline

Published: Jun 15, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-3593?

How severe is CVE-2021-3593?

CVE-2021-3593 has a CVSS score of 3.8/10 (LOW severity). The EPSS model estimates a 0.33% probability of exploitation in the next 30 days.

How do I fix CVE-2021-3593?

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-2021-3593?

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

Scan your code now

Source: NVD / NIST