libmodbus v3.1.10 is vulnerable to Buffer Overflow via the modbus_write_bits function.

published 2024-05-08 2 y ago modified 2026-08-11 2 mo ago also EUVD-2024-34708 , JLSEC-2026-1253

cvss: 7.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.5%; EPSS 0.5% chance of exploitation in 30 days, percentile 44%
public exploits: 0; none known

libmodbus v3.1.10 is vulnerable to Buffer Overflow via the modbus_write_bits function. This issue can be triggered when the function is fed with specially crafted input, which leads to out-of-bounds read and can potentially cause a crash or other unintended behaviors.

Patch / fix

fixed in 1

julia LibModbus_jll 3.1.12+0

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-2024-34244 updated 2026-01-13 cvss 6.5

libmodbus: heap buffer overread

Red Hat All currently supported Red Hat products
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: 2 y ago (2024-05-09)

Exploit prediction

0.52% chance of exploitation in the next 30 days, higher than 44% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/stephane/libmodbus/issues/743 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

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

Affected packages

ecosystem	package	affected	fixed in
julia	LibModbus_jll	>=3.1.10+0, <3.1.12+0	3.1.12+0

Affected products

libmodbus libmodbus

Classification

Weakness

CWE-120 Buffer Copy without Checking Size of Input
CWE-125 Out-of-bounds Read

References

github.com /stephane/libmodbus/issues/743
exploit, issue-tracking, vendor-advisory, web

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.

Summary