CVE-2026-90572
Received Received - Intake

Memory Corruption in Snap7 Library via DataLen Manipulation

Publication date: 2026-09-13

Last updated on: 2026-09-13

Assigner: VulDB

Description
A vulnerability was determined in davenardella snap7 up to 1.4.3. The affected element is the function TSnap7MicroClient::opUpload of the file src/core/s7_micro_client.cpp. Executing a manipulation of the argument DataLen can lead to memory corruption. The attack can be executed remotely. The exploit has been publicly disclosed and may be utilized. The project was informed of the problem early through an issue report but has not responded yet.

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Meta Information

Published
2026-09-13
Last Modified
2026-09-13
Generated
2026-09-13
AI Q&A
2026-09-13
EPSS Evaluated
N/A
NVD
CVE-2026-90572
EUVD
EUVD-2026-77053

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
davenardella snap7 to 1.4.3 (inc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-119 The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.

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Executive Summary

This vulnerability is a memory corruption issue in the Snap7 library up to version 1.4.3. It occurs in the TSnap7MicroClient::opUpload function where the DataLen argument is used directly to calculate the size for a memcpy operation without validation. This can lead to negative or excessively large memory copy sizes, causing crashes or memory corruption in the client application.

Detection Guidance

To detect this vulnerability, monitor for crashes or memory corruption in applications using the Snap7 library, particularly during PLC upload operations. Check for unusual network traffic patterns involving the S7 protocol. Inspect logs for errors related to memcpy operations or invalid DataLen values in the src/core/s7_micro_client.cpp file.

Impact Analysis

The vulnerability can be exploited remotely by a malicious or compromised PLC. It may cause crashes or memory corruption in the client application using the Snap7 library. This could lead to denial of service, data leaks, or arbitrary code execution depending on the application's context and memory layout.

Mitigation Strategies

Immediately update to the latest version of Snap7 if available. If not, apply input validation to ensure DataLen values are within safe bounds before memcpy operations. Restrict network access to PLCs and monitor for suspicious activity. Consider disabling upload functionality if not required.

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