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Fencer Vulns
high 7.5

CVE-2026-44673 json

libyang: lyb_read_string() integer overflow → heap buffer overflow

published 2026-05-14 5 mo ago modified 2026-10-26 13 d ago also EUVD-2026-30484

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 50%
public exploits
0
none known

Summary

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.

Patch / fix

  • Red Hat Red Hat Enterprise Linux 10 0:2.1.148-4.el10_2
  • Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support 0:2.1.148-2.el10_0.1
  • Red Hat Red Hat Enterprise Linux 8 0:1.0.184-2.el8_10
  • Red Hat Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support 0:1.0.184-1.el8_4.1
  • Red Hat Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On 0:1.0.184-1.el8_4.1
  • Red Hat Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support 0:1.0.184-1.el8_6.1
  • Red Hat Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On 0:1.0.184-1.el8_6.1
  • Red Hat Red Hat Enterprise Linux 8.8 Telecommunications Update Service 0:1.0.184-1.el8_8.1
  • Red Hat Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions 0:1.0.184-1.el8_8.1
  • Red Hat Red Hat Enterprise Linux 9 0:2.1.148-1.el9_8.1
  • Red Hat Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions 0:2.1.148-1.el9_2.1
  • Red Hat Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions 0:2.1.148-1.el9_4.1
  • Red Hat Red Hat Enterprise Linux 9.6 Extended Update Support 0:2.1.148-1.el9_6.1
  • libyang Debian 14 6.4.13-1

debian advisories DEBIAN-CVE-2026-44673

  • libyang RHEL 9 2.1.148-1.el9_8.1
  • libyang RHEL 10.2 2.1.148-4.el10_2
  • libyang RHEL 8 1.0.184-2.el8_10
  • libyang RHEL 9.6 EUS 2.1.148-1.el9_6.1
  • libyang RHEL 9.4 E4S 2.1.148-1.el9_4.1
  • libyang RHEL 9.2 E4S 2.1.148-1.el9_2.1
  • libyang RHEL 8.6 EUS_LONG_LIFE, RHEL 8.6 AUS 1.0.184-1.el8_6.1
  • libyang RHEL 8.4 EUS_LONG_LIFE, RHEL 8.4 AUS 1.0.184-1.el8_4.1

red hat advisories RHSA-2026:65508RHSA-2026:65467RHSA-2026:65477RHSA-2026:51368RHSA-2026:51351RHSA-2026:51339

  • libyang SLES 16.0, SLES for SAP applications 16.0 2.1.148-160000.4.1
  • libyang SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS +1 more 1.0.184-150300.3.9.1
  • libyang SLE Module for Server Applications 15 SP7 2.1.148-150700.3.5.1
  • libyang SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES 15 SP6-LTSS +3 more 2.1.55-150500.3.5.1
  • libyang SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 2.1.148-8.8.1

suse advisories SUSE-SU-2026:22200-1SUSE-SU-2026:22208-1SUSE-SU-2026:2381-1SUSE-SU-2026:2337-1SUSE-SU-2026:2335-1SUSE-SU-2026:2334-1

  • libyang openSUSE Leap 16.0 2.1.148-160000.4.1
  • libyang openSUSE Tumbleweed 3.13.6-3.1

opensuse advisories openSUSE-SU-2026:21113-1openSUSE-SU-2026:10880-1

  • libyang AlmaLinux 9 2.1.148-1.el9_8.1
  • libyang AlmaLinux 10 2.1.148-4.el10_2
  • libyang AlmaLinux 8 1.0.184-2.el8_10

almalinux advisories ALSA-2026:25051ALSA-2026:24758ALSA-2026:24545

  • libyang Rocky Linux 9 2.1.148-1.el9_8.1
  • libyang Rocky Linux 10 2.1.148-4.el10_2
  • libyang Rocky Linux 8 1.0.184-2.el8_10

rocky linux advisories RLSA-2026:25051RLSA-2026:24758RLSA-2026:24545

  • libyang Azure Linux 3.0 2.1.148-3

azure linux advisories AZL-86816

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-44673 updated cvss 7.5

libyang: libyang: Denial of Service or arbitrary code execution via maliciously crafted LYB binary blob

  • Red Hat Enterprise Linux AppStream (v. 8) libyang 1.0.184-2.el8_10
    fixed: vendor fix RHSA-2026:24545
  • Red Hat Enterprise Linux AppStream (v. 9) libyang 2.1.148-1.el9_8.1
    fixed: vendor fix RHSA-2026:25051
  • Red Hat Enterprise Linux AppStream (v. 10) libyang 2.1.148-4.el10_2
    fixed: vendor fix RHSA-2026:24758
  • Red Hat Enterprise Linux AppStream AUS (v.8.4) libyang 1.0.184-1.el8_4.1
    fixed: vendor fix RHSA-2026:51351
  • Red Hat Enterprise Linux AppStream AUS (v.8.6) libyang 1.0.184-1.el8_6.1
    fixed: vendor fix RHSA-2026:51368
  • Red Hat Enterprise Linux AppStream E4S (v.8.8) libyang 1.0.184-1.el8_8.1
    fixed: vendor fix RHSA-2026:51339
  • Red Hat Enterprise Linux AppStream E4S (v.9.2) libyang 2.1.148-1.el9_2.1
    fixed: vendor fix RHSA-2026:65477
  • Red Hat Enterprise Linux AppStream E4S (v.9.4) libyang 2.1.148-1.el9_4.1
    fixed: vendor fix RHSA-2026:65467
show 8 more
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) libyang 2.1.148-2.el10_0.1
    fixed: vendor fix RHSA-2026:49666
  • Red Hat Enterprise Linux AppStream EUS (v.9.6) libyang 2.1.148-1.el9_6.1
    fixed: vendor fix RHSA-2026:65508
  • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) libyang 1.0.184-1.el8_4.1
    fixed: vendor fix RHSA-2026:51351
  • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6) libyang 1.0.184-1.el8_6.1
    fixed: vendor fix RHSA-2026:51368
  • Red Hat Enterprise Linux AppStream TUS (v.8.8) libyang 1.0.184-1.el8_8.1
    fixed: vendor fix RHSA-2026:51339
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libyang-devel 2.1.148-1.el9_8.1, libyang-debuginfo 2.1.148-1.el9_8.1, libyang-devel-doc 2.1.148-1.el9_8.1, libyang-debugsource 2.1.148-1.el9_8.1
    fixed: vendor fix RHSA-2026:25051
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libyang-devel 2.1.148-4.el10_2, libyang-debuginfo 2.1.148-4.el10_2, libyang-devel-doc 2.1.148-4.el10_2, libyang-debugsource 2.1.148-4.el10_2, libyang-tools-debuginfo 2.1.148-4.el10_2
    fixed: vendor fix RHSA-2026:24758
  • Red Hat Enterprise Linux AppStream AUS (v.8.4) libyang-debuginfo 1.0.184-1.el8_4.1, libyang-debugsource 1.0.184-1.el8_4.1, libyang-cpp-debuginfo 1.0.184-1.el8_4.1, python3-libyang-debuginfo 1.0.184-1.el8_4.1 Red Hat Enterprise Linux AppStream AUS (v.8.6) libyang-debuginfo 1.0.184-1.el8_6.1, libyang-debugsource 1.0.184-1.el8_6.1, libyang-cpp-debuginfo 1.0.184-1.el8_6.1, python3-libyang-debuginfo 1.0.184-1.el8_6.1 Red Hat Enterprise Linux AppStream E4S (v.8.8) libyang-debuginfo 1.0.184-1.el8_8.1, libyang-debugsource 1.0.184-1.el8_8.1, libyang-cpp-debuginfo 1.0.184-1.el8_8.1, python3-libyang-debuginfo 1.0.184-1.el8_8.1 Red Hat Enterprise Linux AppStream E4S (v.9.2) libyang-debuginfo 2.1.148-1.el9_2.1, libyang-debugsource 2.1.148-1.el9_2.1 Red Hat Enterprise Linux AppStream E4S (v.9.4) libyang-debuginfo 2.1.148-1.el9_4.1, libyang-debugsource 2.1.148-1.el9_4.1 Red Hat Enterprise Linux AppStream EUS (v.9.6) libyang-debuginfo 2.1.148-1.el9_6.1, libyang-debugsource 2.1.148-1.el9_6.1
    +3 more products
    Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) libyang-debuginfo 1.0.184-1.el8_4.1, libyang-debugsource 1.0.184-1.el8_4.1, libyang-cpp-debuginfo 1.0.184-1.el8_4.1, python3-libyang-debuginfo 1.0.184-1.el8_4.1 Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6) libyang-debuginfo 1.0.184-1.el8_6.1, libyang-debugsource 1.0.184-1.el8_6.1, libyang-cpp-debuginfo 1.0.184-1.el8_6.1, python3-libyang-debuginfo 1.0.184-1.el8_6.1 Red Hat Enterprise Linux AppStream TUS (v.8.8) libyang-debuginfo 1.0.184-1.el8_8.1, libyang-debugsource 1.0.184-1.el8_8.1, libyang-cpp-debuginfo 1.0.184-1.el8_8.1, python3-libyang-debuginfo 1.0.184-1.el8_8.1
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
5 mo ago

Exploit prediction

0.64% chance of exploitation in the next 30 days, higher than 50% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/CESNET/libyang/security/advisories/GHSA-vw2p-pq79-92xh referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • CESNET libyang
  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
  • Red Hat Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On
  • Red Hat Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support
  • Red Hat Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On
  • Red Hat Red Hat Enterprise Linux 8.8 Telecommunications Update Service
  • Red Hat Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 9.6 Extended Update Support

Classification

Weakness
  • CWE-190 Integer Overflow or Wraparound

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.