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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| libyang | libyang | < 5.4.3 | 5.4.3 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | libyang | 6.4.13-1 | — |
| Debian 13 | libyang | No fix yet | — |
| Debian 12 | libyang2 | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.04 LTS | libyang | 3.13.6-1ubuntu0.1 | USN-8485-1 |
| Ubuntu 25.10 | libyang | 3.13.5-2ubuntu0.1 | USN-8485-1 |
| Ubuntu 22.04 LTS | libyang | No fix yet | — |
| Ubuntu 20.04 LTS | libyang | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | libyang | 2.1.148-150700.3.5.1 | SUSE-SU-2026:2337-1 |
| SLES 15 SP6 | libyang | 2.1.55-150500.3.5.1 | SUSE-SU-2026:2335-1 |
| SLES 15 SP5 | libyang | 2.1.55-150500.3.5.1 | SUSE-SU-2026:2335-1 |
| SLES 12 SP5 | libyang | 2.1.148-8.8.1 | SUSE-SU-2026:2334-1 |
Show 5 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | libyang | 2.1.148-160000.4.1 | SUSE-SU-2026:22208-1, SUSE-SU-2026:22200-1 |
| SLES for SAP 15 SP6 | libyang | 2.1.55-150500.3.5.1 | SUSE-SU-2026:2335-1 |
| SLES for SAP 15 SP5 | libyang | 2.1.55-150500.3.5.1 | SUSE-SU-2026:2335-1 |
| SLES 16.0 | libyang | 2.1.148-160000.4.1 | SUSE-SU-2026:22208-1, SUSE-SU-2026:22200-1 |
| SLE HPC 15 SP5 | libyang | 2.1.55-150500.3.5.1 | SUSE-SU-2026:2335-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | libyang | 3.13.6-2.1 | openSUSE-SU-2026:10868-1 |
| openSUSE Leap 16.0 | libyang | 2.1.148-160000.4.1 | openSUSE-SU-2026:21113-1 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | libyang | 2.1.148-3 | — |
Advisories 8
- USN-8485-1 libyang vulnerability Ubuntu Security Notices (USN) · Jun 30, 2026
- openSUSE-SU-2026:21113-1 Security update for libyang SUSE / openSUSE Security Updates · Jun 30, 2026
- SUSE-SU-2026:22200-1 Security update for libyang SUSE / openSUSE Security Updates · Jun 24, 2026
- SUSE-SU-2026:22208-1 Security update for libyang SUSE / openSUSE Security Updates · Jun 24, 2026
- SUSE-SU-2026:2334-1 Security update for libyang SUSE / openSUSE Security Updates · Jun 11, 2026
- SUSE-SU-2026:2335-1 Security update for libyang SUSE / openSUSE Security Updates · Jun 11, 2026
- SUSE-SU-2026:2337-1 Security update for libyang SUSE / openSUSE Security Updates · Jun 11, 2026
- openSUSE-SU-2026:10868-1 libyang-devel-3.13.6-2.1 on GA media SUSE / openSUSE Security Updates · May 28, 2026
References
- GitHub Security Advisory (GHSA-9f49-8x56-jmjc) vendor-advisory
- https://github.com/CESNET/libyang/commit/6b5ed47ee674fbe86b31bbebc4ff26889aeff38c patch
- Anthropic CVD Finding ANT-2026-TZQ1KH7E third-party-advisory
- VulnCheck Advisory: libyang - Heap Use-After-Free Write in XML Metadata Parsing third-party-advisory