Medium 6.5Published May 26, 2026

CVE-2026-41401libyang - Heap Use-After-Free Write in XML Metadata Parsing

Updated under an hour ago (Oct 26, 2026, 5:00 PM ET)

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No exploitation reported and no EPSS estimate yet.

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Every CVE for libyang

Exploited in the last 30 days

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.

CVSS: 6.5 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-416
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: VulnCheck
NVD analysis: Deferred
Record last updated: May 26, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

libyang libyang libyang:libyang (from the name)	before 5.4.3; 5.4.3 not affected	CNA record

References

References

https://github.com/CESNET/libyang/security/advisories/GHSA-9f49-8x56-jmjc	vendor-advisory
https://github.com/CESNET/libyang/commit/6b5ed47ee674fbe86b31bbebc4ff26889aeff38c	patch
https://red.anthropic.com/2026/cvd/findings/ANT-2026-TZQ1KH7E	third-party-advisory
https://www.vulncheck.com/advisories/libyang-heap-use-after-free-write-in-xml-metadata-parsing	third-party-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.