NULL pointer dereference in libyang - #VU163173
Published: November 9, 2026
Vulnerability identifier: #VU163173
CSH Severity: Medium
CVSS v4: 6.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-476
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows an attacker who controls a YANG schema to crash applications that parse it with libyang, causing denial of service.
The vulnerability exists due to a NULL-pointer dereference in libyang's extension-statement parser when a text-field substatement within an extension instance contains a nested extension instance. An attacker who controls a YANG schema can trigger the crash by having an application parse this crafted input.
Affected software
libyang
Remediation
Install security update from vendor's website.
libyang - update to 5.8.6