SB2026052046 - Uncontrolled Recursion in libyang

Description

This security bulletin contains information about 1 vulnerability.

1) Uncontrolled Recursion (CVE-ID: N/A)

CWE-ID: CWE-674 - Uncontrolled Recursion

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to uncontrolled recursion in lyplg_type_store_union when processing a YANG module containing a union value with a circular leaf reference during default value validation. A remote attacker can supply a specially crafted YANG module to cause a denial of service.

The issue is triggered during parsing via lys_parse_mem() when a self-referential leafref is used inside a union type and a default value causes type validation.

Remediation

Install update from vendor's website.

References

• https://github.com/CESNET/libyang/security/advisories/GHSA-mq87-gwqp-w3v8
• https://github.com/advisories/GHSA-mq87-gwqp-w3v8