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.
Fix
Patch, vendor advisory and mitigation references on NVD 1
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 6.9 · libyangNVD modified 2026-10-29 20:19
Affected (CPE criteria) 0
NVD has not attached CPE configurations yet.
References 4
- 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