Multiple Windows 11 customers and IT administrators report weird VPN behavior in the latest cumulative updates. According to Reddit and Microsoft Support forums posts, installing the May 2023 Patch Tuesday updates cripples VPN connection speed, subsequently crippling other features, such as RDP.
No problems connecting to the VPN, just once you get in the speeds are extremely slow and RDP basically just times out. A quick search of the web confirms that KB5025305 causes speed issues on L2TP/IPsec VPN.
---
Our users are facing this, with a strange oddity: a group of 5-6 users is able to get 100m down and 80m up speeds, but the vast majority get sub 1m down and sub 1m up speeds.
Some affected users claim the unknown bug only affects Wi-Fi connections, and systems using wired internet continue operating VPNs without problems.
A Microsoft spokesperson has said (via) that the company is aware of the problem and is looking into it. Unfortunately, they have not provided any possible workarounds, so the only option for those suffering from a snail-like VPN connection is to uninstall the problematic updates or sit tight, waiting for a fix from Microsoft.
It appears that VPN slowdowns are not the only problem with the latest Patch Tuesday updates. Some users report seeing cryptic errors when installing available updates, and others complain about notable SSD speed downgrades.