Just the other week, ExpressVPN, one of the industry leading VPN services, had to take its split-tunneling feature down for Windows users due to a DNS leak issue. The problem is believed to have first begun with version 12.23.1 way back in May of 2022, but wasn’t noticed until recently.
While the DNS leaks were confirmed by ExpressVPN, it was believed to be a relatively small number of users, around 1 percent, who were affected.
Windows users can breathe a sigh of relief though, as according to ExpressVPN the issue has now been resolved. Split-tunneling is once again available to Windows users after the service’s engineering team was able to identify and fix the issue.
According to an in-depth blog post on the company’s website, the problem was ruled to not be a result of external factors but apparently caused by two separate internal issues.
ExpressVPN stated, “The first issue was introduced when we built our split-tunneling feature for Version 12 of the ExpressVPN Windows app (this issue was never present in Version 10). In every instance, the DNS cache service should have been automatically directed to use the VPN. However, when split tunneling was activated in “Only allow selected apps to use the VPN” mode, the DNS cache service was allowed to operate outside the VPN, which meant that some DNS requests might be misdirected.”
“The second issue was caused by the presence of other VPN apps on a Windows device. When other VPN apps were installed, even if they were not in active use, it was possible for their filtering rules to affect the performance of our app. This cross-contamination only occurred when split tunneling was turned on. We improved the filtering logic to eliminate potential DNS leaks with split tunneling.”
After extensive in-house testing, ExpressVPN has released two updated versions, Version 12.74.0 and Version 10.51.0 with the bug fixes. It is recommended that all Windows users update these apps as soon as possible.
Author: Sam Singleton, Assistant Editor, PCWorld
Sam Singleton is PCWorld's VPN beat reporter and jack of all trades. When he's not on the hunt for the best computer deals he's covering VPNs, productivity software, laptops, and a wide gamut of consumer-grade hardware and software.