The development of modern software-defined networking (SDN) solutions brings new opportunities in Internet-of-Vehicles (IoVs). However, the autonomous nature of the vehicular environment leads to unpredictable security vulnerabilities and reliability issues. The high computation overhead and storage requirements also pose a significant challenge in message dissemination. To overcome these issues, we introduce a lightweight blockchain-based security protocol for secure communication and storage in SDN-enabled IoV, known as LBSV. The LBSV is a permissioned blockchain network that uses the proposed modified practical byzantine fault tolerance (mPBFT) consensus algorithm. Additionally, the SDN-enabled network exploits the blockchain framework and schedules different procedures. The secure message dissemination is achieved through various cryptographic functions (i.e., elliptic curve cryptography (ECC) and the secure hash algorithm (SHA256)). The security analysis shows that the LBSV withstands various cyberattacks regarding message dissemination privacy. The experimental results show that LBSV provides high performance with 85% less computational cost, 55% less storage and communication overhead and 90% less consensus delay compared with state-of-the-art schemes.