# CVE-2026-44673: libyang: lyb_read_string() integer overflow → heap buffer overflow > An integer overflow in libyang's LYB parser allows attackers to trigger heap buffer overflows, potentially leading to code execution or crashes. - **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 14 May 2026 - **Updated:** 9 Sep 2026 - **Also known as:** ALSA-2026:24545, ALSA-2026:24758, ALSA-2026:25051, AZL-86816, DEBIAN-CVE-2026-44673, MINI-9h7p-9h5w-5m34, RHSA-2026:24545, RHSA-2026:24758, RHSA-2026:25051, RHSA-2026:49666, RHSA-2026:51339, RHSA-2026:51351, RHSA-2026:51368, RHSA-2026:65467, RHSA-2026:65477, RHSA-2026:65508, RLSA-2026:24545, RLSA-2026:24758, RLSA-2026:25051, SUSE-SU-2026:2381-1, openSUSE-SU-2026:10880-1 ## 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 (Integer Overflow or Wraparound) ## Which versions are affected by CVE-2026-44673? | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `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. ## Fix prompt for AI coding agents ```text 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) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-44673 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-44673 - OSV: https://osv.dev/vulnerability/CVE-2026-44673 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-44673/ Summaries are generated and may contain mistakes; the official description above is the record.