Mayur021

snap7 through 1.4.3 contains an out-of-bounds write vulnerability in TSnap7MicroClient::opReadArea() that allows malicious S7 peers to overflow client buffers via an unchecked DataLength field. Rogue or impersonated PLCs can return crafted ReadVar responses causing memcpy of up to 65535 bytes into caller buffers, crashing SCADA, HMI, or gateway processes and corrupting memory.

**Name of the Vulnerable Software and Affected Versions** davenardella snap7 versions prior to 1.4.4 **Description** A remote attack can cause memory corruption by manipulating the `DataLen` argument within the `TSnap7MicroClient::opUpload()` function located in the src/core/s7 micro client.cpp file. **Recommendations** As a temporary workaround, restrict the use of the `TSnap7MicroClient::opUpload()` function to minimize the risk of exploitation. At the moment, there is no information about a newer version that contains a fix for this vulnerability.