CVE-2020-1983: libslirp: use after free vulnerability cause a denial of service.

Published Apr 2, 2020
·
Updated

A use after free vulnerability in ipreass() in ipinput.c of libslirp 4.2.0 and prior releases allows crafted packets to cause a denial of service.

Other sources

A use-after-free flaw was found in the SLiRP networking implementation of the QEMU emulator. Specifically, this flaw occurs in the ipreass() routine while reassembling incoming IP fragments whose combined size is bigger than 65k. This flaw allows an attacker to crash the QEMU process on the host, resulting in a denial of service.

Affected Software

17 affected componentsFixes available
redhat/qemu-kvm<10:1.5.3-175.el7_9.1
10:1.5.3-175.el7_9.1
redhat/qemu-kvm-ma<10:2.12.0-48.el7_9.2
10:2.12.0-48.el7_9.2
redhat/qemu-kvm-rhev<10:2.12.0-48.el7_9.2
10:2.12.0-48.el7_9.2
redhat/libslirp<4.3.0
4.3.0
Libslirp Project Libslirp<=4.2.0
Fedoraproject Fedora=31
Fedoraproject Fedora=32
Debian Debian Linux=8.0
Debian Debian Linux=9.0
openSUSE Leap=15.1
Canonical Ubuntu Linux=16.04
Canonical Ubuntu Linux=18.04
Canonical Ubuntu Linux=19.10
Canonical Ubuntu Linux=20.04
debian/libslirp
4.4.0-1+deb11u24.7.0-14.8.0-14.9.1-1
debian/qemu
1:5.2+dfsg-11+deb11u31:5.2+dfsg-11+deb11u51:7.2+dfsg-7+deb12u181:7.2+dfsg-7+deb12u151:10.0.7+ds-0+deb13u11:10.0.2+ds-2+deb13u11:10.2.1+ds-1
debian/slirp4netns
1.0.1-21.2.0-11.2.1-1.11.3.3-1

Event History

Apr 2, 2020
CVE Published
12:00 AM
Apr 22, 2020
CVE Published
via MITRE·07:30 PM
Data Sourced
via MITRE·07:30 PM
DescriptionSeverityWeakness
Feb 20, 2026
Data Sourced
via Ubuntu·11:28 PM
RemedyDescriptionSeverityAffected Software
Data Sourced
via Launchpad·11:28 PM
Description
Feb 23, 2026
Data Sourced
via Debian·11:31 PM
DescriptionAffected Software
Free Weekly Intel

Don't miss critical vulnerabilities

Join thousands of security professionals who receive our weekly digest of trending CVEs, zero-days, and exploited vulnerabilities.

No spam. Unsubscribe anytime.

Frequently Asked Questions

1

What is CVE-2020-1983?

CVE-2020-1983 is a use after free vulnerability in ip_reass() in ip_input.c of libslirp 4.2.0 and prior releases.

2

What is the severity of CVE-2020-1983?

The severity of CVE-2020-1983 is high, with a CVSS score of 6.5.

3

How does CVE-2020-1983 affect the QEMU emulator?

CVE-2020-1983 can cause the QEMU process on the host to crash.

4

How can I fix CVE-2020-1983?

To fix CVE-2020-1983, update to libslirp version 4.3.0 or later.

5

Where can I find more information about CVE-2020-1983?

You can find more information about CVE-2020-1983 at the following references: [link1], [link2], [link3].

Contact

SecAlerts Pty Ltd.
132 Wickham Terrace
Fortitude Valley,
QLD 4006, Australia
info@secalerts.co
By using SecAlerts services, you agree to our services end-user license agreement. This website is safeguarded by reCAPTCHA and governed by the Google Privacy Policy and Terms of Service. All names, logos, and brands of products are owned by their respective owners, and any usage of these names, logos, and brands for identification purposes only does not imply endorsement. If you possess any content that requires removal, please get in touch with us.
© 2026 SecAlerts Pty Ltd.
ABN: 70 645 966 203, ACN: 645 966 203