macOS: AmneziaVPN-service crashes with SIGSEGV on connection attempt, leaving network unreachable

[Wooden210]

Environment

• macOS Sequoia 15.7.7 (24G720)
• AmneziaVPN 4.8.15.4 (2edd7de)
• Hardware: MacBook Pro 17,1 (x86_64 via Rosetta 2)
• Protocol: AmneziaWG (amnezia-awg2 container)

Behavior

When pressing "Connect", AmneziaVPN-service crashes with SIGSEGV, leaving the routing table broken and the entire network unreachable until reboot.

Crash happens multiple times per session (confirmed in DiagnosticReports).

Crash info

Exception: EXC_BAD_ACCESS (SIGSEGV) — KERN_INVALID_ADDRESS at 0x0000000000000008

Faulting stack trace:

DaemonLocalServerConnection::write(QJsonObject const&)
DaemonLocalServerConnection::disconnected()         ← null ptr dereference here
DaemonLocalServerConnection::parseCommand(QByteArray const&)
DaemonLocalServerConnection::readData()
QAbstractSocketPrivate::canReadNotification()
QCoreApplication::sendEvent()
QEventDispatcherUNIX::processEvents()
QEventLoop::exec()
QCoreApplication::exec()
main

Root cause

Race condition: when a new connection attempt is initiated while a previous one is still deactivating, disconnected() is called on a DaemonLocalServerConnection object that has already been freed/nulled, causing a null pointer dereference at offset +8.

Visible in app log:

[17:42:50] LocalSocketController: Deactivating
[17:42:50] VpnProtocol::setConnectionState "Отключено"
[17:42:50] LocalSocketController: Deactivating    ← second call while first still in progress
[17:42:50] VpnProtocol::setConnectionState "Отключено"

Network impact

After crash, routing table contains stale entries:

0/1      utun4   ← all traffic routed to dead VPN interface
128.0/1  utun4

This blocks all internet traffic. KeepAlive=true restarts the daemon, but stale routes remain, requiring full reboot to recover.

Steps to reproduce

1. Have an AmneziaWG connection configured
2. Click "Connect"
3. While connecting, click "Connect" again or let it fail and retry quickly

Expected behavior

Service should not crash; on disconnect/retry it should safely handle already-freed connection objects. On service crash, routes should be cleaned up (e.g. via launchd cleanup handler).

[nedlis94-prog]

+1, confirming the same crash on macOS 26.4.1 (build 25E253) on MacBook Air M4 (Apple Silicon, arm64).

Setup:

• Hardware: MacBook Air M4 (Mac16,12)
• OS: macOS 26.4.1 (25E253)
• Amnezia client: tested on 4.8.12 and 4.8.15.4 (both crash, both are x86_64 running under Rosetta 2)
• Protocol: AmneziaWG Legacy

Symptoms:

• GUI shows "Connecting…" indefinitely on AmneziaWG Legacy.
• utun4 interface comes up with MTU 1376 but never gets an IPv4 address — handshake doesn't complete.
• On Xray protocol the GUI reports "Connected" but no traffic flows (tun2socks creates the local interface, but AmneziaVPN-service
  can't establish outbound TCP — lsof shows dozens of sockets stuck in SYN_SENT to the server endpoint).
• The same servers/configs work perfectly on iPhone (iOS Amnezia) and Windows (Amnezia 4.8.12) on the same Wi-Fi.
• Worked stably for ~6 months until May 20, 2026. Crashed for the first time at 12:03 MSK that day. Has been broken since.

Crash signatures (attached .ips files):

AmneziaVPN (4.8.12), 2026-05-20 12:03:21:

• Exception: EXC_BAD_ACCESS (SIGSEGV), KERN_INVALID_ADDRESS at 0x000000000000006e
• Faulting thread: QThread, frames include XrayProtocol::stop(), VpnConnection::disconnectFromVpn(),
  IpcProcessTun2SocksReplica::setConnectionState(int)
• translated: true (Rosetta 2)

AmneziaVPN-service, 2026-05-22 13:59:53:

• Exception: EXC_BAD_ACCESS (SIGSEGV), KERN_INVALID_ADDRESS at 0x0000000000000008
• Faulting thread (main): DaemonLocalServerConnection::readData() → _sigtramp
• Go-runtime frames in other threads (runtime.findRunnable, runtime.schedule, etc.)
• translated: true (Rosetta 2)

What I tried (didn't help):

• Full uninstall + clean reinstall (5x), including manual removal of
  ~/Library/Preferences/{com.yourcompany,org.amneziavpn}.AmneziaVPN.plist, ~/Library/Caches/AmneziaVPN.ORG,
  /Library/LaunchDaemons/AmneziaVPN.plist, /Library/Application Support/AmneziaVPN.
• Tried both 4.8.12 (.dmg) and 4.8.15.4 (.pkg) — same crash signatures.
• Tested with mobile hotspot — same result, so it's not the local network or the ISP.
• System is clean: no config profiles (profiles show -type configuration empty), pfctl disabled, no third-party VPN clients
  installed.

Workaround:
Switched to the native AmneziaWG app from the Mac App Store (id6478942365 by Privacy Technologies OU) — works fine, no crashes. This
confirms the issue is specific to the x86_64 amnezia-client build under Rosetta 2, not to the AmneziaWG protocol or the server.

Please consider shipping a native arm64 build of amnezia-client — this would resolve the issue at the root for all M-series Mac users.