CVE-2026-41401

libyang - Heap Use-After-Free Write in XML Metadata Parsing

MEDIUM
6.5
CVSS Score
Published: May 26, 2026 at 02:08 PM UTC
Updated: July 24, 2026 at 11:23 AM UTC
2 products affected across 2 vendorsLibyangLibyang

Using libyang by libyang?

Get instant alerts when new vulnerabilities affect libyang - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Severity
MEDIUM6.5
Exploit prediction
EPSS 0.7%
SSVC
PoC

Description

libyang before 5.2.6 contains a heap use-after-free write vulnerability in lyd_parser_set_data_flags that incorrectly updates metadata list pointers when freeing non-head default metadata entries. Attackers can trigger this vulnerability by submitting crafted YANG XML documents with specific metadata attributes to applications parsing untrusted XML data, causing process crashes or potential code execution.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 5.4.3
Affected range stops below 5.4.3, so it looks safe — our inference, not a vendor statement
v < 5.4.3
Vendor states this is fixed in 5.4.3 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.5MEDIUMVulnCheck
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-416

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Free plan, no card