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  4. CVE 2026 41401 libyang heap use after free write in xml metadata
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Back to active CVEs
Medium · CVSS 6.9CVE-2026-41401

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

Answer in brief

CVE-2026-41401 records a Medium severity (CVSS 6.9) vulnerability in libyang - Heap Use-After-Free Write in XML Metadata Parsing. The current sources do not mark it as known exploited. The current feed maps libyang/libyang (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published May 26, 2026Updated Oct 29, 2026Source checked Oct 29, 2026First seen by HOL Oct 29, 2026Material review Oct 29, 2026
Upstream Advisory

Key facts

Risk
Medium · CVSS 6.9
Exploitation
Not marked as known exploited
Affected software
1 mapped package or product
Fix availability
Available

Why this deserves its current priority

CVSS is 6.9. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps libyang/libyang (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
PackageAffected rangeFixed version
libyang/libyanggeneric>=0 <5.4.35.4.3

Recommended response

  1. 1Check inventory. Check lockfiles and deployed manifests for libyang/libyang.
  2. 2Review the reported fix. Update libyang/libyang to 5.4.3 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

  1. Published upstream

    May 26, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  2. Source modified

    Oct 29, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  3. First seen by HOL

    Oct 29, 2026

Sources and claim methodology

  • GitHub security advisorygithub.com
  • GitHub security advisorygithub.com
  • Source referencered.anthropic.com
  • Source referencevulncheck.com
Upstream source description

libyang before 5.4.3 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.

Quoted source text, attributed separately from HOL analysis.

Record context

Vulnerability class
Memory Corruption
EPSS
Not reported
CWE IDs
CWE-416
Source
CVE List V5
Source checked
Oct 29, 2026
References
4 linked sources
Open source record