CVE-2019-20398

Name: CVE-2019-20398
Creator: NVD / NIST
Published: 2020-01-22T22:15:10.627+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 1.82%

Last modified Jun 17, 2026

CVE-2019-20398 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. A NULL pointer dereference is present in libyang before v1.0-r3 in the function lys_extension_instances_free() due to a copy of unresolved extensions in lys_restr_dup(). Applications that use libyang to parse untrusted input yang files may crash.. EPSS estimates a 1.82% chance of exploitation in the next 30 days.

Description

A NULL pointer dereference is present in libyang before v1.0-r3 in the function lys_extension_instances_free() due to a copy of unresolved extensions in lys_restr_dup(). Applications that use libyang to parse untrusted input yang files may crash.

Metrics

CVSS 3.1

6.5/10

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

EPSS Probability

1.82%

76.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-476

Affected Software

Vendor	Product	Versions	Update
Cesnet	Libyang	0.11	R1
Cesnet	Libyang	0.12	R1
Cesnet	Libyang	0.13	R1
Cesnet	Libyang	0.14	R1
Cesnet	Libyang	0.15	R1
Cesnet	Libyang	0.16	R1
Cesnet	Libyang	1.0	R1

References

https://bugzilla.redhat.com/show_bug.cgi?id=1793935Issue Tracking, Patch, Third Party Advisory
https://github.com/CESNET/libyang/commit/7852b272ef77f8098c35deea6c6f09cb78176f08Patch
https://github.com/CESNET/libyang/compare/v1.0-r2...v1.0-r3Third Party Advisory
https://github.com/CESNET/libyang/issues/773Exploit, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2023/09/msg00019.html
https://bugzilla.redhat.com/show_bug.cgi?id=1793935Issue Tracking, Patch, Third Party Advisory
https://github.com/CESNET/libyang/commit/7852b272ef77f8098c35deea6c6f09cb78176f08Patch
https://github.com/CESNET/libyang/compare/v1.0-r2...v1.0-r3Third Party Advisory
https://github.com/CESNET/libyang/issues/773Exploit, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2023/09/msg00019.html

Timeline

Published: Jan 22, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2019-20398?

How severe is CVE-2019-20398?

CVE-2019-20398 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 1.82% probability of exploitation in the next 30 days.

How do I fix CVE-2019-20398?

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-2019-20398?

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

Scan your code now

Source: NVD / NIST