Any app on recent Android versions can leak certain traffic

A recently discovered bug in Android 16 allows any app to leak traffic outside the VPN tunnel.

The bug was reported to the Android Security Team, but was closed as Won’t Fix (Infeasible) [...] In contrast, GrapheneOS, a security-focused Android-based OS, quickly patched the issue in its codebase.

A mitigation is possible, but is quite technical in that it requires USB debugging to be enabled on the device in order to run the following Android Debug Bridge (adb) commands:

adb shell device_config put tethering close_quic_connection -1

adb reboot

https://mullvad.net/en/blog/2026/5/12/any-app-on-recent-android-versions-can-leak-certain-trafficOpen link View original on lemmy.zip

Comments5

massive_bereavement

fedia.io

Yeah, haha sure, a bug... 🙄

WhatAmLemmy reply

lemmy.world

"We're sorry" ((rubs nips))

acido

feddit.it

nice, gonna use the fix as soon as I get home.

EDIT:

This disables the QUIC graceful shutdown feature, and thus closes the leak. The mitigation will persist across reboots, but it may be undone by system updates, in which case the steps will need to be repeated.

Performing this mitigation means that the server-side QUIC socket will remain half-open until it times out, which should generally not negatively affect the Android device or apps running on it. However, only use the command at your own risk if you understand the implications.

anyone knows the implications of this?

MagicDonkey reply

lemmy.dbzer0.com

My guess is if the server side connection stays half open it would mean the server is still sending data to your device after its closed the connection causing that data to essentially get sinkhole'd.

Maybe in some extreme examples if you have a huge amount of connections that get abruptly closed your bandwidth could be limited until the connections expire. In normal circumstances that probably just means a small amount of additional background resources are getting wasted.

SillyDude

lemmy.zip

Android 16 introduced a bug

Security via poverty, like I can even run andriod 16 😎