Which Language Is Safest? Findings from the Latest Open‑Source Vulnerability Report

2019 Open‑Source Language Vulnerability Rankings

The 2019 Open‑Source Software Vulnerability State report shows a 50% increase in total vulnerabilities, rising from 4,100 in 2018 to 6,100 in 2019. The most common flaw is cross‑site scripting (XSS, CWE‑79), which dominates across popular programming languages.

Buffer overflows rank first among error types, followed by improper input validation.

Vulnerability Ratios by Language

The report also examines the distribution of open‑source security flaws among popular languages.

C language accounts for more than 30% of the reported vulnerabilities, largely because it is one of the oldest languages and is used in many high‑profile open‑source projects such as the Linux kernel, Wireshark, and ImageMagick.

PHP shows a striking increase: its share grew from 15% in the 2009‑2018 period to 27% in 2019. This raises two questions: why is PHP so vulnerable, and how widely is it actually used?

According to the 2019 Tiobe ranking, PHP’s ease of use attracts developers with limited software‑development experience, boosting its popularity but also exposing a trade‑off between usability and security. Major applications like WordPress, Magento, Joomla, and Drupal are built with PHP.

Strengthening Open‑Source Code Security

Vulnerability counts keep rising as codebases grow and more community members review them. Automated tools are needed to discover and fix flaws quickly, and platforms such as GitHub Security Lab allow developers to submit vulnerability reports directly.

Older open‑source projects (e.g., PHP‑based WordPress and Drupal) are being re‑examined, revealing long‑standing bugs that had never been reported.

No best language, only better coding practices.

Security flaws are essentially bugs that compromise application integrity, confidentiality, or availability. Most arise from careless coding, and as long as humans write code, bugs and vulnerabilities will persist.

The key is not to search for a “most secure” language but to manage vulnerabilities effectively and adopt secure coding standards throughout the software development lifecycle.

Developers should be educated on best practices, perform thorough code reviews, and prioritize testing, especially for critical functionality, to mitigate severe security issues.