Home Assistant integration fails: JSON API binds to IPv6 only + memory leak suspected

[Starbase12]

• I confirm that this is an issue rather than a question.

Bug report

Steps to reproduce

1. Having Hyperion 2.1.1 (updated) running on a Raspbian 12 system.
2. Ensure JSON API server (Port 19444) is enabled in network config.
3. Partly deactivate ipv6 (for ens192) interface.
4. Ensure that net.ipv6.bindv6only = 0 (Dual-Stack is supported) is not set to 1.
5. Start hyperion-daemon and check with "netstat -tulpn | grep 19444". First I noticed that only tcp6 is listening for 19444. Other ports was Dual-Stack (ipv6 and ipv4 listening). I have fixed this behavior while completly disable IPv6.
6. Try to connect Home Assistant OS (core-2025.7.1) to the Hyperion JSON API.
7. Leave Hyperion running for several hours without any device connected.

What is expected?

• The Home Assistant integration should be able to connect to Hyperion via the JSON API on port 19444.
• Hyperion should not consume excessive memory if no device is active.
• With Dual-Stack support enabled, Hyperion should listen properly on both IPv4 and IPv6 also for 19444.

What is actually happening?

• Home Assistant OS (latest stable) fails to connect to the JSON API, even though port 19444 is shown as listening on TCP.
• Over time, Hyperion consumes all system RAM and SWAP, despite not actively controlling any device. This resembles a memory leak and was only noticed my monitoring software warns me.
• Initially, Hyperion only listened on TCP6 for port 19444 (IPv6 only). This appears to be a regression, since in previous versions the port was accessible via IPv4 as well. Disabling IPv6 globally forces Hyperion to fall back to IPv4, which resolves the LISTENING but not connectivity issue.

System

Hyperion Server:

• Build: LordGrey-bde49a8/26fd6d8-1749918223
• Build time: Jun 14 2025 16:59:30
• Build type: Release
• Git Remote: https://github.com/hyperion-project/hyperion.ng
• Version: 2.1.1
• UI Lang: de (BrowserLang: de)
• UI Access: expert
• Avail Screen Cap.: dispmanx,framebuffer,qt
• Avail Video Cap.: v4l2
• Avail Audio Cap.: audio
• Avail Services: boblight,cec,effectengine,forwarder,flatbuffer,protobuffer,mDNS,SSDP,borderdetection
• Config database: /root/.hyperion/db/hyperion.db
• Database: read/write
• Mode: Non-GUI

Hyperion Server OS:

• Distribution: Debian GNU/Linux 12 (bookworm)
• Architecture: arm64
• CPU Type: Raspberry Pi 4 Model B Rev 1.1
• CPU Revision: b03111
• Kernel: linux (6.12.25+rpt-rpi-v8 (WS: 64))
• Root/Admin: true
• Qt Version: 6.4.2
• Python Version: 3.11.2
• Browser: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:140.0) Gecko/20100101 Firefox/140.0

[Paulchen-Panther]

Can you please provide us with your config?
Thank you very much.

[Lord-Grey]

Are you running Hyperion and HA in different LAN segments, e.g. using VLANs; then you are hit by the following issue #1880.
You can work around by enabling Internet Access or test PR #1884