Bottom line: The US Cybersecurity and Infrastructure Security Agency is once again reminding IT manufacturers and developers that buffer overflow vulnerabilities must be eradicated from software. In short, companies need to adopt a "secure by design" policy and fast. CISA has issued a new alert about buffer overflow vulnerabilities, urging the software industry to adopt proper programming practices to eliminate an entire class of dangerous security flaws. Buffer overflow exploits frequently lead to system compromise, CISA warns, posing significant threats to system reliability, data integrity, and overall cybersecurity.A buffer overflow occurs when a threat actor can access or write data outside a program's allocated memory space, CISA explained. If hackers manipulate memory beyond a buffer's allocated limits, it can lead to data corruption, exposure of sensitive information, system crashes, or even remote execution of malicious code.CISA previously warned about buffer overflow vulnerabilities and is now reiterating its message. The agency highlights real-world examples of these flaws, including vulnerabilities in Windows operating systems (CVE-2025-21333), the Linux kernel (CVE-2022-0185), VPN products (CVE-2023-6549), and various other software environments where executable code is present.Software companies can combat the buffer overflow threat by adopting a proper "secure by design" approach when writing their code. In software engineering, "secure by design" means that products and features are built with security as a foundational principle rather than added as an afterthought. However, CISA noted that only a few companies have implemented this approach so far.The agency outlined several "secure by design" practices that technical leads should adopt within their organizations. These include using memory-safe programming languages such as Rust or Go, configuring compilers to detect buffer overflow bugs before deployment, and conducting regular product testing. // Related StoriesCISA, along with other government agencies including the FBI and the NSA, are offering additional resources and reports to help companies mitigate buffer overflow vulnerabilities and other critical security threats.The agency also highlighted three broad "secure by design" principles developed in collaboration with 17 global cybersecurity organizations. These principles emphasize full accountability in the software development process, a "radical" commitment to transparency, and organizational structures designed to prioritize security.