From 093a79045d606d12a257483fe7c3d63cbf9a1ddd Mon Sep 17 00:00:00 2001
From: Cody Henthorne <cody@signal.org>
Date: Fri, 20 Feb 2026 14:05:41 -0500
Subject: [PATCH] Fix incorrect sender key state for mismatch/stale devices.

---
 .../signalservice/api/SignalServiceMessageSender.java  | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/lib/libsignal-service/src/main/java/org/whispersystems/signalservice/api/SignalServiceMessageSender.java b/lib/libsignal-service/src/main/java/org/whispersystems/signalservice/api/SignalServiceMessageSender.java
index e7be79e5e8..ff5c8e9ef3 100644
--- a/lib/libsignal-service/src/main/java/org/whispersystems/signalservice/api/SignalServiceMessageSender.java
+++ b/lib/libsignal-service/src/main/java/org/whispersystems/signalservice/api/SignalServiceMessageSender.java
@@ -2924,6 +2924,11 @@ public class SignalServiceMessageSender {
       Log.w(TAG, "[handleMismatchedDevices] Address: " + recipient.getIdentifier() + ", ExtraDevices: " + mismatchedDevices.getExtraDevices() + ", MissingDevices: " + mismatchedDevices.getMissingDevices());
       archiveSessions(recipient, mismatchedDevices.getExtraDevices());
 
+      ArrayList<Integer> mismatchedDeviceIds = new ArrayList<>();
+      mismatchedDeviceIds.addAll(mismatchedDevices.getExtraDevices());
+      mismatchedDeviceIds.addAll(mismatchedDevices.getMissingDevices());
+      clearSenderKeySharedWith(recipient, mismatchedDeviceIds);
+
       for (int missingDeviceId : mismatchedDevices.getMissingDevices()) {
         PreKeyBundle preKey = NetworkResultUtil.toPreKeysLegacy(keysApi.getPreKey(recipient, missingDeviceId));
 
@@ -2942,6 +2947,7 @@ public class SignalServiceMessageSender {
   private void handleStaleDevices(SignalServiceAddress recipient, StaleDevices staleDevices) {
     Log.w(TAG, "[handleStaleDevices] Address: " + recipient.getIdentifier() + ", StaleDevices: " + staleDevices.getStaleDevices());
     archiveSessions(recipient, staleDevices.getStaleDevices());
+    clearSenderKeySharedWith(recipient, staleDevices.getStaleDevices());
   }
 
   public void handleChangeNumberMismatchDevices(@Nonnull MismatchedDevices mismatchedDevices)
@@ -2958,6 +2964,10 @@ public class SignalServiceMessageSender {
     }
   }
 
+  private void clearSenderKeySharedWith(SignalServiceAddress recipient, List<Integer> deviceIds) {
+    aciStore.clearSenderKeySharedWith(convertToProtocolAddresses(recipient, deviceIds));
+  }
+
   private List<SignalProtocolAddress> convertToProtocolAddresses(SignalServiceAddress recipient, List<Integer> devices) {
     List<SignalProtocolAddress> addresses = new ArrayList<>(devices.size());