dbcve.org
Integer OverflowWeakness · CWE-190

CVE-2026-44673

HIGH · 7.5 CVSS v3.1 Published 2026-05-14
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Integer overflow in lyb_read_string() in src/parser_lyb.c allows heap buffer overflow when parsing malicious LYB binary blobs, potentially causing crash or heap corruption in libyang consumers like NETCONF servers and sysrepo.

MitigationUpgrade to SO 5.2.15 or later to obtain the fix. Until patched, strictly validate and restrict sources of LYB data input to prevent processing of untrusted binary blobs.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed libyang version
    Run 'pkg-config --modversion libyang' or check the library file version with 'ldd' on the NETCONF/sysrepo binary, or look for libyang package version with your system package manager
    Affected if The version is lower than 5.2.15 (or version cannot be determined and libyang is present)
  2. Determine if LYB parsing is in use
    Inspect application configuration files or logs for references to .lyb files, or check if the application loads LYB-encoded data schemas or configurations from any input source
    Affected if The application processes LYB binary blobs from any external or network source
  3. Check for NETCONF or sysrepo service exposure
    Identify if a NETCONF server (such as ConfD, OpenDaylight, or custom NETCONF implementations) or sysrepo instance is running and accessible over network ports 830 (NETCONF over SSH) or other management interfaces
    Affected if The service accepts LYB-encoded configuration or schema data from network clients
  4. Verify input validation on LYB data sources
    Review application logs for crashes or heap errors related to LYB parsing, or test the LYB parser with the CVE PoC if available
    Affected if The LYB parser crashes, exhibits heap corruption symptoms, or accepts LYB data without cryptographic integrity verification

You are affected if you run libyang versions prior to 5.2.15 and your application or service parses LYB binary blobs from untrusted or network-accessible sources.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade to SO 5.2.15 or later to obtain the fix. Until patched, strictly validate and restrict sources of LYB data input to prevent processing of untrusted binary blobs.

Recommended fix Moderate confidence

SO 5.2.15 (sysrepo 5.2.15) or libyang version containing the fix

  1. Identify the current version of libyang or sysrepo installed on the system using the package manager (e.g., rpm -q libyang, dpkg -l libyang, or yum list installed libyang)
  2. Upgrade the libyang package to version 5.2.15 or later using the appropriate package manager (e.g., yum update libyang, apt-get install libyang, or dnf update libyang)
  3. If the system uses sysrepo, ensure sysrepo is also updated to version 5.2.15 or later to incorporate the fixed libyang library
  4. After upgrading, restart any services that use libyang (such as NETCONF servers or sysrepo daemons) to load the fixed library
  5. Verify the upgrade was successful by checking the installed version (e.g., rpm -q libyang)
Caveat Review release notes for 5.2.15 to check for any API/ABI changes that may require updates to dependent applications

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA3.0 h
16.0 hours of engineering $2,760
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-44673 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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