What’s Vulnerable › Vulnerabilities

CVE-2026-54410: nanoMODBUS Off-by-One Buffer Overflow in recv_msg_header() via Crafted MBAP Length Field

• Severity: high (CVSS 8.6 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-06-14 · updated 2026-08-10
• Weakness: CWE-193

Description

nanoMODBUS through v1.23.0 contains an off-by-one buffer overflow in the recv_msg_header function of the Modbus/TCP server that allows remote unauthenticated attackers to write one attacker-controlled byte past the end of the 260-byte receive buffer by sending a crafted MBAP frame whose Length field is set to 255.

Affected products

• debevv nanoMODBUS: through 1.23.0

References

• https://cwe.mitre.org/data/definitions/193.html
• https://cwe.mitre.org/data/definitions/787.html
• https://github.com/debevv/nanoMODBUS
• https://github.com/debevv/nanoMODBUS/blob/v1.23.0/nanomodbus.c#L369

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