CVE-2025-41730: CRITICAL Severity Vulnerability | Secably CVE Database

Summary

CVE-2025-41730 is a critical vulnerability affecting WAGO devices. It allows an unauthenticated remote attacker to achieve full device compromise by exploiting unsafe `sscanf` calls within the `check_account()` function, leading to arbitrary data writes into fixed-size stack buffers.

Technical Details

This vulnerability stems from the use of `sscanf` within the `check_account()` function of the affected WAGO firmware. The `sscanf` function, when used without proper input validation, is susceptible to buffer overflows. An attacker can send a specially crafted request containing overly long strings that are then parsed by `sscanf` and written into fixed-size stack buffers. Because the buffers are of a predetermined size, an attacker can overwrite adjacent memory locations on the stack, including return addresses. By overwriting the return address, the attacker can redirect program execution to an arbitrary location in memory, effectively achieving remote code execution. The lack of authentication required to trigger this vulnerability significantly increases its severity.

The vulnerability is triggered by sending a network request that is processed by the `check_account()` function. This function uses `sscanf` to parse the request and extract user account information. The attacker crafts a request with excessively long account details, causing `sscanf` to write beyond the bounds of the allocated stack buffers. This overwrite allows the attacker to control the execution flow of the device.

Affected Products and Versions

The following WAGO products and firmware versions are known to be affected by CVE-2025-41730:

WAGO 0852-1328_firmware
WAGO 0852-1322_firmware

It is possible that other WAGO products using similar firmware versions are also affected. Users are advised to check with WAGO for a complete list of affected devices.

Impact Assessment

Successful exploitation of CVE-2025-41730 can lead to a complete compromise of the affected WAGO device. This includes:

Remote Code Execution: The attacker can execute arbitrary code on the device, allowing them to install malware, modify system configurations, or use the device as a launchpad for further attacks.
Denial of Service (DoS): The attacker can crash the device, rendering it unavailable for its intended purpose.
Data Breach: The attacker can access sensitive data stored on the device, including configuration files, credentials, and other confidential information.
Lateral Movement: Compromised devices can be used to gain access to other systems on the network.

Remediation

It is crucial to apply the necessary patches or workarounds as soon as possible to mitigate the risk posed by CVE-2025-41730.

Immediate Actions

Apply Patches: WAGO has released firmware updates to address this vulnerability. Immediately apply the latest firmware updates to all affected devices.
Network Segmentation: Isolate affected devices from the rest of the network to limit the potential impact of a successful attack.
Monitor Network Traffic: Monitor network traffic for suspicious activity, such as unusual network connections or attempts to exploit the vulnerability.

Long-term Solutions

Implement Input Validation: Ensure that all input data is properly validated to prevent buffer overflows and other vulnerabilities.
Secure Coding Practices: Follow secure coding practices to minimize the risk of introducing vulnerabilities into the firmware.
Regular Security Audits: Conduct regular security audits to identify and address potential vulnerabilities.

References

VDE CERT Advisory VDE-2025-095

Detection & Scanning

Detecting CVE-2025-41730 requires careful analysis of network traffic and device logs. Look for suspicious network requests targeting the `check_account()` function with excessively long account details. Vulnerability scanners can also be used to identify affected devices.

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