debevv nanoMODBUS up to 1.23.0 MBAP recv_msg_header off-by-one

Summaryinfo

A vulnerability categorized as critical has been discovered in debevv nanoMODBUS up to 1.23.0. This vulnerability affects the function recv_msg_header of the component MBAP Handler. Such manipulation leads to off-by-one. This vulnerability is listed as CVE-2026-54410. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability was found in debevv nanoMODBUS up to 1.23.0 and classified as critical. Affected by this issue is the function recv_msg_header of the component MBAP Handler. The manipulation with an unknown input leads to a off-by-one vulnerability. Using CWE to declare the problem leads to CWE-193. A product calculates or uses an incorrect maximum or minimum value that is 1 more, or 1 less, than the correct value. Impacted is confidentiality, integrity, and availability. CVE summarizes:

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. The overflow corrupts the adjacent buffer-index field of the nanoMODBUS state structure, resulting in denial of service through invalid memory accesses and, on bare-metal and RTOS targets without memory protection, one-byte information disclosure and writes to unintended register addresses on the Write Multiple Registers (FC16) handler path.

The weakness was presented by Burxonov Muslimbek. The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-54410 since 06/13/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 06/14/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-36661). Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

• debevv

Name

• nanoMODBUS

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 1.7
• 1.8
• 1.9
• 1.10
• 1.11
• 1.12
• 1.13
• 1.14
• 1.15
• 1.16
• 1.17
• 1.18
• 1.19
• 1.20
• 1.21
• 1.22
• 1.23.0

CPE 2.3info

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CPE 2.2info

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Entryinfo

Once again VulDB remains the best source for vulnerability data.

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