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NVD / CVE Program· CNA GitHub_M

CVE-2026-44673: libyang: lyb_read_string() integer overflow → heap buffer overflow

Noroxi assessment

Priority: Monitor (action score 30/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.63% (FIRST EPSS); higher than 50.4% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: azl3 libyang 2.1.148-1 on Azure Linux 3.0 2.1.148-2.

Low priority for now. Upgrade to azl3 libyang 2.1.148-1 on Azure Linux 3.0 2.1.148-2 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

HighCVSS 7.5 · v3.1—No exploit Fix available
Published
May 14, 2026
Updated
Oct 26, 2026
EPSS
0.6% · 50th percentile

Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.6%

CISA SSVC decision

Exploitation
proof of concept
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
7.5
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-44673

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
enterprise linux10.2
enterprise linux eus10.0
enterprise linux8
rhel aus8.4
rhel eus long life8.4
rhel aus8.6
rhel eus long life8.6
rhel tus8.8
rhel e4s8.8
enterprise linux9
rhel e4s9.2
rhel e4s9.4

and 1 more

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • CESNET libyang

    • < SO 5.2.15affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:10libyangbefore 2.1.148-4.el10_22.1.148-4.el10_2
AlmaLinux:10libyang-develbefore 2.1.148-4.el10_22.1.148-4.el10_2
AlmaLinux:10libyang-devel-docbefore 2.1.148-4.el10_22.1.148-4.el10_2
AlmaLinux:8libyangbefore 1.0.184-2.el8_101.0.184-2.el8_10
AlmaLinux:9libyangbefore 2.1.148-1.el9_8.12.1.148-1.el9_8.1
AlmaLinux:9libyang-develbefore 2.1.148-1.el9_8.12.1.148-1.el9_8.1
AlmaLinux:9libyang-devel-docbefore 2.1.148-1.el9_8.12.1.148-1.el9_8.1
Debian:12libyang2from 0—
Debian:13libyangfrom 0—
Debian:14libyangbefore 6.4.13-16.4.13-1
openSUSE:Leap 16.0libyangbefore 2.1.148-160000.4.12.1.148-160000.4.1
openSUSE:Tumbleweedlibyangbefore 3.13.6-3.13.13.6-3.1
Red Hat:enterprise_linux_eus:10.0libyangbefore 0:2.1.148-2.el10_0.10:2.1.148-2.el10_0.1
Red Hat:enterprise_linux_eus:10.0libyang-debuginfobefore 0:2.1.148-2.el10_0.10:2.1.148-2.el10_0.1
Red Hat:enterprise_linux_eus:10.0libyang-debugsourcebefore 0:2.1.148-2.el10_0.10:2.1.148-2.el10_0.1
Red Hat:enterprise_linux_eus:10.0libyang-tools-debuginfobefore 0:2.1.148-2.el10_0.10:2.1.148-2.el10_0.1
Red Hat:enterprise_linux:10.2libyangbefore 0:2.1.148-4.el10_20:2.1.148-4.el10_2
Red Hat:enterprise_linux:10.2libyang-debuginfobefore 0:2.1.148-4.el10_20:2.1.148-4.el10_2
Red Hat:enterprise_linux:10.2libyang-debugsourcebefore 0:2.1.148-4.el10_20:2.1.148-4.el10_2
Red Hat:enterprise_linux:10.2libyang-develbefore 0:2.1.148-4.el10_20:2.1.148-4.el10_2
Red Hat:enterprise_linux:10.2libyang-devel-docbefore 0:2.1.148-4.el10_20:2.1.148-4.el10_2
Red Hat:enterprise_linux:10.2libyang-tools-debuginfobefore 0:2.1.148-4.el10_20:2.1.148-4.el10_2
Red Hat:enterprise_linux:8::appstreamlibyangbefore 0:1.0.184-2.el8_100:1.0.184-2.el8_10
Red Hat:enterprise_linux:8::appstreamlibyang-cpp-debuginfobefore 0:1.0.184-2.el8_100:1.0.184-2.el8_10

+22

Same product

cesnet: all records

Other highest-scoring records for the same primary product.

  • CVE-2019-19334In all versions of libyang before 1.0-r5, a stack-based buffer overflow was discovered in the way libyang parses YANG files with a leaf of t
    40Plan
  • CVE-2019-19333In all versions of libyang before 1.0-r5, a stack-based buffer overflow was discovered in the way libyang parses YANG files with a leaf of t
    40Plan
  • CVE-2019-20397A double-free is present in libyang before v1.0-r1 in the function yyparse() when an organization field is not terminated.
    36Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2023-26916Apr 3, 2023 · libyang from v2.0.164 to v2.1.30 was discovered to contain a NULL pointer dereference via the function lys_parse_mem at lys_parse_mem.c.
    21Monitor
  • ← EarlierCVE-2023-26917Apr 11, 2023 · libyang from v2.0.164 to v2.1.30 was discovered to contain a NULL pointer dereference via the function lysp_stmt_validate_value at lys_parse
    30Monitor
  • Later →CVE-2026-115327Oct 22, 2026 · libyang through 6.4.13 Uninitialized Pointer Free in NETCONF RPC Parser
    24Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
azl3 libyang 2.1.148-1 on Azure Linux 3.02.1.148-2 · CBL-Mariner ReleasesMicrosoft (MSRC)
almalinux:libyang1.0.184-2.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:libyang-devel2.1.148-4.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:libyang-devel-doc2.1.148-4.el10_2 · AlmaLinux:10Package registry (OSV)
debian:libyang6.4.13-1 · Debian:14Package registry (OSV)
opensuse:libyang3.13.6-3.1 · openSUSE:TumbleweedPackage registry (OSV)
red hat:libyang0:1.0.184-2.el8_10 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:libyang-cpp-debuginfo0:1.0.184-2.el8_10 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:libyang-debuginfo0:1.0.184-2.el8_10 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:libyang-debugsource0:1.0.184-2.el8_10 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:libyang-devel0:2.1.148-4.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:libyang-devel-doc0:2.1.148-4.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:libyang-tools-debuginfo0:2.1.148-4.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:python3-libyang-debuginfo0:1.0.184-2.el8_10 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
rocky linux:libyang0:1.0.184-2.el8_10 · Rocky Linux:8Package registry (OSV)
suse:libyang2.1.148-160000.4.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-190 · Integer Overflow or Wraparound

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (13 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records