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.

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
libyang libyang unaffected
Version Status Constraints
0 affected < 5.4.3
5.4.3 unaffected —

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Project Subscriptions

Vendors Products
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Libyang Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/CESNET/libyang/commit/6b5ed47ee674fbe86b31bbebc4ff26889aeff38c cve-icon cve-icon
https://github.com/CESNET/libyang/security/advisories/GHSA-9f49-8x56-jmjc cve-icon cve-icon
https://red.anthropic.com/2026/cvd/findings/ANT-2026-TZQ1KH7E cve-icon cve-icon
https://www.vulncheck.com/advisories/libyang-heap-use-after-free-write-in-xml-metadata-parsing cve-icon cve-icon
History

Tue, 26 May 2026 14:30:00 +0000

Type Values Removed Values Added
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.
Title libyang - Heap Use-After-Free Write in XML Metadata Parsing
First Time appeared Cesnet
Cesnet libyang
Weaknesses CWE-416
CPEs cpe:2.3:a:cesnet:libyang:*:*:*:*:*:*:*:*
Vendors & Products Cesnet
Cesnet libyang
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-05-26T14:14:49.472Z

Reserved: 2026-04-20T14:15:22.223Z

Link: CVE-2026-41401

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-05-26T15:16:35.660

Modified: 2026-05-26T15:16:35.660

Link: CVE-2026-41401

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-26T16:00:11Z

Weaknesses