CVE-2026-44673 libyang: lyb_read_string() integer overflow → heap buffer overflow
High 7.5
Published
Updated
Check this codebase for CVE-2026-44673 and fix it if it is affected.
What it is: CVE-2026-44673 is a high-severity vulnerability in CESNET libyang, published on 14 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-44673 exists.
Affected product: CESNET libyang. No package-level version data is available, so check the vendor advisory linked from the reference page.
Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.
Reference: https://insights.sbomify.com/CVE-2026-44673/ (Markdown: https://insights.sbomify.com/CVE-2026-44673/index.md)
An integer overflow in libyang's LYB parser allows attackers to trigger heap buffer overflows, potentially leading to code execution or crashes.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-44673?
CVE-2026-44673 is a high-severity vulnerability in CESNET libyang, published on 14 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
libyang is a YANG data modeling language library. Prior to SO 5.2.15, lyb_read_string() in src/parser_lyb.c contains an integer overflow that results in a heap buffer overflow when parsing a maliciously crafted LYB binary blob. An attacker who can supply LYB data to any libyang consumer (NETCONF server, sysrepo, etc.) can trigger a crash or potential heap corruption. This vulnerability is fixed in SO 5.2.15.
Weakness: CWE-190
Which versions are affected by CVE-2026-44673?
Linux distribution packages (40)
libyang AlmaLinux:10 | All versions | 2.1.148-4.el10_2 |
libyang-devel AlmaLinux:10 | All versions | 2.1.148-4.el10_2 |
libyang-devel-doc AlmaLinux:10 | All versions | 2.1.148-4.el10_2 |
libyang AlmaLinux:8 | All versions | 1.0.184-2.el8_10 |
libyang AlmaLinux:9 | All versions | 2.1.148-1.el9_8.1 |
libyang-devel AlmaLinux:9 | All versions | 2.1.148-1.el9_8.1 |
libyang-devel-doc AlmaLinux:9 | All versions | 2.1.148-1.el9_8.1 |
libyang Red Hat:enterprise_linux:10.2 | All versions | 0:2.1.148-4.el10_2 |
libyang-debuginfo Red Hat:enterprise_linux:10.2 | All versions | 0:2.1.148-4.el10_2 |
libyang-debugsource Red Hat:enterprise_linux:10.2 | All versions | 0:2.1.148-4.el10_2 |
libyang-devel Red Hat:enterprise_linux:10.2 | All versions | 0:2.1.148-4.el10_2 |
libyang-devel-doc Red Hat:enterprise_linux:10.2 | All versions | 0:2.1.148-4.el10_2 |
libyang-tools-debuginfo Red Hat:enterprise_linux:10.2 | All versions | 0:2.1.148-4.el10_2 |
libyang Red Hat:enterprise_linux:8::appstream | All versions | 0:1.0.184-2.el8_10 |
libyang-cpp-debuginfo Red Hat:enterprise_linux:8::appstream | All versions | 0:1.0.184-2.el8_10 |
libyang-debuginfo Red Hat:enterprise_linux:8::appstream | All versions | 0:1.0.184-2.el8_10 |
libyang-debugsource Red Hat:enterprise_linux:8::appstream | All versions | 0:1.0.184-2.el8_10 |
python3-libyang-debuginfo Red Hat:enterprise_linux:8::appstream | All versions | 0:1.0.184-2.el8_10 |
libyang Red Hat:enterprise_linux:9::appstream | All versions | 0:2.1.148-1.el9_8.1 |
libyang-debuginfo Red Hat:enterprise_linux:9::appstream | All versions | 0:2.1.148-1.el9_8.1 |
libyang-debugsource Red Hat:enterprise_linux:9::appstream | All versions | 0:2.1.148-1.el9_8.1 |
libyang-debuginfo Red Hat:enterprise_linux:9::crb | All versions | 0:2.1.148-1.el9_8.1 |
libyang-debugsource Red Hat:enterprise_linux:9::crb | All versions | 0:2.1.148-1.el9_8.1 |
libyang-devel Red Hat:enterprise_linux:9::crb | All versions | 0:2.1.148-1.el9_8.1 |
libyang-devel-doc Red Hat:enterprise_linux:9::crb | All versions | 0:2.1.148-1.el9_8.1 |
libyang Red Hat:enterprise_linux_eus:10.0 | All versions | 0:2.1.148-2.el10_0.1 |
libyang-debuginfo Red Hat:enterprise_linux_eus:10.0 | All versions | 0:2.1.148-2.el10_0.1 |
libyang-debugsource Red Hat:enterprise_linux_eus:10.0 | All versions | 0:2.1.148-2.el10_0.1 |
libyang-tools-debuginfo Red Hat:enterprise_linux_eus:10.0 | All versions | 0:2.1.148-2.el10_0.1 |
libyang Red Hat:rhel_aus:8.4::appstream | All versions | 0:1.0.184-1.el8_4.1 |
libyang Red Hat:rhel_aus:8.6::appstream | All versions | 0:1.0.184-1.el8_6.1 |
libyang Red Hat:rhel_e4s:8.8::appstream | All versions | 0:1.0.184-1.el8_8.1 |
libyang Red Hat:rhel_e4s:9.2::appstream | All versions | 0:2.1.148-1.el9_2.1 |
libyang Red Hat:rhel_e4s:9.4::appstream | All versions | 0:2.1.148-1.el9_4.1 |
libyang Red Hat:rhel_eus:9.6::appstream | All versions | 0:2.1.148-1.el9_6.1 |
libyang Red Hat:rhel_eus_long_life:8.4::appstream | All versions | 0:1.0.184-1.el8_4.1 |
libyang Red Hat:rhel_eus_long_life:8.6::appstream | All versions | 0:1.0.184-1.el8_6.1 |
libyang Red Hat:rhel_tus:8.8::appstream | All versions | 0:1.0.184-1.el8_8.1 |
libyang Rocky Linux:10 | All versions | 0:2.1.148-4.el10_2 |
libyang Rocky Linux:8 | All versions | 0:1.0.184-2.el8_10 |
How do I fix CVE-2026-44673?
Upgrade to a fixed version.
Is CVE-2026-44673 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-44673 exists.
Sources
Also known as ALSA-2026:24545, ALSA-2026:24758, ALSA-2026:25051, AZL-86816, DEBIAN-CVE-2026-44673, MINI-9h7p-9h5w-5m34 and 15 more.