More than half of Windows virtual private network applications include OpenVPN code that has not been updated in over a year, leaving millions of users potentially exposed to documented security flaws and compatibility issues, according to a recent software audit. OpenVPN serves as an open-source foundational protocol that routes and encrypts data between user devices and remote servers. Because many commercial VPN providers update their user interfaces and client features while leaving the core tunneling component untouched, core dependencies can fall years behind upstream security releases.
To evaluate the scope of outdated software bundling, an independent technical audit examined 32 Windows VPN clients this July. The review encompassed software ranging from major multinational corporations to smaller utility apps and free services. The findings revealed that 56%—representing 18 out of the 32 evaluated clients—rely on an OpenVPN version more than a year old. Furthermore, 41% (14 clients) utilize configurations older than two years, 22% (7 clients) depend on code exceeding four years, and 12.5% (4 clients) run software components that are at least five years old.
Disparities across the industry are pronounced. Well-resourced providers including NordVPN, Windscribe, and Proton VPN maintain OpenVPN builds as recent as April 2026. Conversely, services such as Turbo VPN and VyprVPN continue to incorporate OpenVPN 2.4.7, a release originally issued in April 2019.
The Security Risks of Outdated Cryptographic Dependencies
Running legacy protocol code introduces measurable operational and security liabilities. Marijus Briedis, Chief Technology Officer at NordVPN, explained that because upstream projects regularly patch vulnerabilities and harden codebases, running outdated iterations means missing critical security enhancements. Jason Xu, a senior app developer at Windscribe, noted that publicly documented vulnerabilities present an immediate vector for exploitation because attackers can inspect publicly available project changelogs without needing to discover novel zero-day flaws.
Data from upstream development shows that OpenVPN registered six vulnerability advisories in 2025, six in 2024, one in 2023, and one in 2022. Software packages failing to incorporate these upstream updates miss corresponding security fixes. However, technical risks involve structural nuances. An older build may remain unaffected by specific vulnerabilities if it lacks the functional features associated with those flaws. Briedis noted that maintainers can mitigate risks through backported patches, vendor-applied fixes, or configuration adjustments, though verifying whether providers implement such mitigations remains challenging for end-users.
Additional maintenance burdens compound the problem. Dr. Peter Membrey, Chief Research Officer at ExpressVPN, pointed out that older protocol dependencies become increasingly difficult to integrate with modern operating systems and cryptographic libraries, creating a growing baseline of operational and security debt.
Why VPN Providers Delay Upgrades
Adopting new OpenVPN iterations is not a trivial drop-in process. It requires rigorous compatibility testing across different operating systems, regression checks, staged rollouts, and extensive validation of the software stack. Karolis Kaciulis, a leading system engineer at Surfshark, noted that development delays ranging from six to 18 months can be reasonable if critical vulnerabilities are addressed promptly. NortonVPN stated that major updates require careful testing to ensure they deliver clear benefits without introducing stability or performance regressions for customers.
Other providers cited architectural reasons for sticking with older baselines. StrongVPN reported that development work on proprietary internal protocols temporarily postponed its planned transition to OpenVPN 2.7. ClearVPN stated that it relies on internal security patching to maintain protection. PureVPN indicated it remains on OpenVPN 2.6.12 because it engineered custom proprietary technologies around that version, and because newer releases dropped support for the Wintun driver.
How Users Can Audit and Protect Their Connections
Industry shifts toward alternative protocols offer users additional security options. Many commercial services now default to WireGuard or custom proprietary protocols that benefit from more active code maintenance. Proton VPN maintains up-to-date OpenVPN builds on its Windows application, though company representatives noted that the protocol is heavier than modern alternatives like WireGuard and Stealth, prompting long-term plans to phase out OpenVPN client support while retaining it on servers for legacy hardware compatibility.
Users wishing to verify their software’s security posture can audit their VPN clients by inspecting application settings, diagnostic logs, or official release notes to identify the specific OpenVPN version in use. Protocol dependencies older than 12 to 18 months without documented architectural justifications serve as a primary indicator of delayed maintenance. Consumers seeking clarity can also contact provider support desks directly to request transparent patch timelines.
Readers are encouraged to share their experiences or ask questions in the comments below.
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