What is CVE-2023-26793?

CVE-2023-26793 is a critical-severity vulnerability in Libmodbus, classified under Heap-based Buffer Overflow. CVSS score: 9.8/10. Published 2024-05-01.

How severe is CVE-2023-26793?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Buffer overflow in Libmodbus

CVE-2023-26793

libmodbus v3.1.10 has a heap-based buffer overflow vulnerability in read_io_status function in src/modbus.c.

Vulnerability class: Buffer Overflow

Published 2024-05-01 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.007 (52.5th percentile), scored 2026-10-02.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 52nd percentile — 52.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000

Affected products

Libmodbus — versions 3.1.10

Weakness classification (CWE)

CWE-122 — Heap-based Buffer Overflow

References

github.com/stephane/libmodbus/issues/683 (Exploit, Issue Tracking, Vendor Advisory)

Frequently asked questions

What is CVE-2023-26793?: CVE-2023-26793 is a critical-severity vulnerability in Libmodbus, classified under Heap-based Buffer Overflow. CVSS score: 9.8/10. Published 2024-05-01.
How severe is CVE-2023-26793?: Critical severity. CVSS v3 base score is 9.8 out of 10.