diff --git a/r5dev/engine/client/cl_rcon.cpp b/r5dev/engine/client/cl_rcon.cpp
index 47c73480..12fdb2f9 100644
--- a/r5dev/engine/client/cl_rcon.cpp
+++ b/r5dev/engine/client/cl_rcon.cpp
@@ -256,7 +256,8 @@ void CRConClient::ProcessBuffer(const char* pRecvBuf, int nRecvLen, CConnectedNe
 				pData->m_RecvBuffer[3]);
 			pData->m_nPayloadRead = 0;
 
-			if (pData->m_nPayloadLen < 0)
+			if (pData->m_nPayloadLen < 0 ||
+				pData->m_nPayloadLen > pData->m_RecvBuffer.max_size())
 			{
 				Error(eDLL_T::CLIENT, "RCON Cmd: sync error (%d)\n", pData->m_nPayloadLen);
 				this->Disconnect(); // Out of sync (irrecoverable).
diff --git a/r5dev/engine/server/sv_rcon.cpp b/r5dev/engine/server/sv_rcon.cpp
index 3116d2c4..e2ec24e4 100644
--- a/r5dev/engine/server/sv_rcon.cpp
+++ b/r5dev/engine/server/sv_rcon.cpp
@@ -404,7 +404,8 @@ void CRConServer::ProcessBuffer(const char* pRecvBuf, int nRecvLen, CConnectedNe
 				}
 			}
 
-			if (pData->m_nPayloadLen < 0)
+			if (pData->m_nPayloadLen < 0 ||
+				pData->m_nPayloadLen > pData->m_RecvBuffer.max_size())
 			{
 				Error(eDLL_T::SERVER, "RCON Cmd: sync error (%d)\n", pData->m_nPayloadLen);
 				this->CloseConnection(); // Out of sync (irrecoverable).
diff --git a/r5dev/netconsole/netconsole.cpp b/r5dev/netconsole/netconsole.cpp
index 1362f7d3..39a058ee 100644
--- a/r5dev/netconsole/netconsole.cpp
+++ b/r5dev/netconsole/netconsole.cpp
@@ -372,7 +372,8 @@ void CNetCon::ProcessBuffer(const char* pRecvBuf, int nRecvLen, CConnectedNetCon
 				pData->m_RecvBuffer[3]);
 			pData->m_nPayloadRead = 0;
 
-			if (pData->m_nPayloadLen < 0)
+			if (pData->m_nPayloadLen < 0 ||
+				pData->m_nPayloadLen > pData->m_RecvBuffer.max_size())
 			{
 				std::cout << "RCON Cmd: sync error (" << pData->m_nPayloadLen << ")" << std::endl;
 				this->Disconnect(); // Out of sync (irrecoverable).