diff --git a/app/src/main/java/org/thoughtcrime/securesms/messages/DataMessageProcessor.kt b/app/src/main/java/org/thoughtcrime/securesms/messages/DataMessageProcessor.kt
index 8ca06d701e..052b4d4259 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/messages/DataMessageProcessor.kt
+++ b/app/src/main/java/org/thoughtcrime/securesms/messages/DataMessageProcessor.kt
@@ -897,7 +897,7 @@ object DataMessageProcessor {
 
     SignalDatabase.messages.beginTransaction()
     try {
-      val quote: QuoteModel? = getValidatedQuote(context, envelope.timestamp!!, message)
+      val quote: QuoteModel? = getValidatedQuote(context, envelope.timestamp!!, message, senderRecipient, threadRecipient)
       val contacts: List<Contact> = getContacts(message)
       val linkPreviews: List<LinkPreview> = getLinkPreviews(message.preview, message.body ?: "", false)
       val mentions: List<Mention> = getMentions(message.bodyRanges.take(BODY_RANGE_PROCESSING_LIMIT))
@@ -1077,7 +1077,7 @@ object DataMessageProcessor {
     return SignalDatabase.messages.insertMessageInbox(textMessage).orNull()
   }
 
-  fun getValidatedQuote(context: Context, timestamp: Long, message: DataMessage): QuoteModel? {
+  fun getValidatedQuote(context: Context, timestamp: Long, message: DataMessage, senderRecipient: Recipient, threadRecipient: Recipient): QuoteModel? {
     val quote: DataMessage.Quote = message.quote ?: return null
 
     if (quote.id == null) {
@@ -1088,7 +1088,7 @@ object DataMessageProcessor {
     val authorId = Recipient.externalPush(ServiceId.parseOrThrow(quote.authorAci!!)).id
     var quotedMessage = SignalDatabase.messages.getMessageFor(quote.id!!, authorId) as? MmsMessageRecord
 
-    if (quotedMessage != null && !quotedMessage.isRemoteDelete) {
+    if (quotedMessage != null && isSenderValid(quotedMessage, timestamp, senderRecipient, threadRecipient) && !quotedMessage.isRemoteDelete) {
       log(timestamp, "Found matching message record...")
 
       val attachments: MutableList<Attachment> = mutableListOf()
@@ -1127,7 +1127,7 @@ object DataMessageProcessor {
         QuoteModel.Type.fromProto(quote.type),
         quotedMessage.messageRanges
       )
-    } else if (quotedMessage != null) {
+    } else if (quotedMessage != null && quotedMessage.isRemoteDelete) {
       warn(timestamp, "Found the target for the quote, but it's flagged as remotely deleted.")
     }
 
@@ -1144,6 +1144,21 @@ object DataMessageProcessor {
     )
   }
 
+  private fun isSenderValid(quotedMessage: MmsMessageRecord, timestamp: Long, senderRecipient: Recipient, threadRecipient: Recipient): Boolean {
+    if (threadRecipient.isGroup) {
+      val groupRecord = SignalDatabase.groups.getGroup(threadRecipient.id).orNull()
+      if (groupRecord != null && !groupRecord.members.contains(senderRecipient.id)) {
+        warn(timestamp, "Sender is not in the group! Thread: ${quotedMessage.threadId} Sender: ${senderRecipient.id}")
+        return false
+      }
+    } else if (senderRecipient.id != threadRecipient.id) {
+      warn(timestamp, "Sender is not a part of the 1:1 thread! Thread: ${quotedMessage.threadId} Sender: ${senderRecipient.id}")
+      return false
+    }
+
+    return true
+  }
+
   fun getContacts(message: DataMessage): List<Contact> {
     return message.contact.map { ContactModelMapper.remoteToLocal(it) }
   }
diff --git a/app/src/main/java/org/thoughtcrime/securesms/messages/MessageContentProcessor.kt b/app/src/main/java/org/thoughtcrime/securesms/messages/MessageContentProcessor.kt
index 8bbc965679..2cb2bfede6 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/messages/MessageContentProcessor.kt
+++ b/app/src/main/java/org/thoughtcrime/securesms/messages/MessageContentProcessor.kt
@@ -446,6 +446,7 @@ open class MessageContentProcessor(private val context: Context) {
         SyncMessageProcessor.process(
           context,
           senderRecipient,
+          threadRecipient,
           envelope,
           content,
           metadata,
diff --git a/app/src/main/java/org/thoughtcrime/securesms/messages/SyncMessageProcessor.kt b/app/src/main/java/org/thoughtcrime/securesms/messages/SyncMessageProcessor.kt
index f5ef7ca7f7..6723ad5ac9 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/messages/SyncMessageProcessor.kt
+++ b/app/src/main/java/org/thoughtcrime/securesms/messages/SyncMessageProcessor.kt
@@ -136,6 +136,7 @@ object SyncMessageProcessor {
   fun process(
     context: Context,
     senderRecipient: Recipient,
+    threadRecipient: Recipient,
     envelope: Envelope,
     content: Content,
     metadata: EnvelopeMetadata,
@@ -144,7 +145,7 @@ object SyncMessageProcessor {
     val syncMessage = content.syncMessage!!
 
     when {
-      syncMessage.sent != null -> handleSynchronizeSentMessage(context, envelope, content, metadata, syncMessage.sent!!, senderRecipient, earlyMessageCacheEntry)
+      syncMessage.sent != null -> handleSynchronizeSentMessage(context, envelope, content, metadata, syncMessage.sent!!, senderRecipient, threadRecipient, earlyMessageCacheEntry)
       syncMessage.request != null -> handleSynchronizeRequestMessage(context, syncMessage.request!!, envelope.timestamp!!)
       syncMessage.read.isNotEmpty() -> handleSynchronizeReadMessage(context, syncMessage.read, envelope.timestamp!!, earlyMessageCacheEntry)
       syncMessage.viewed.isNotEmpty() -> handleSynchronizeViewedMessage(context, syncMessage.viewed, envelope.timestamp!!)
@@ -174,6 +175,7 @@ object SyncMessageProcessor {
     metadata: EnvelopeMetadata,
     sent: Sent,
     senderRecipient: Recipient,
+    threadRecipient: Recipient,
     earlyMessageCacheEntry: EarlyMessageCacheEntry?
   ) {
     log(envelope.timestamp!!, "Processing sent transcript for message with ID ${sent.timestamp!!}")
@@ -227,7 +229,7 @@ object SyncMessageProcessor {
           threadId = SignalDatabase.threads.getOrCreateThreadIdFor(getSyncMessageDestination(sent))
         }
         dataMessage.hasRemoteDelete -> DataMessageProcessor.handleRemoteDelete(context, envelope, dataMessage, senderRecipient.id, earlyMessageCacheEntry)
-        dataMessage.isMediaMessage -> threadId = handleSynchronizeSentMediaMessage(context, sent, envelope.timestamp!!)
+        dataMessage.isMediaMessage -> threadId = handleSynchronizeSentMediaMessage(context, sent, envelope.timestamp!!, senderRecipient, threadRecipient)
         else -> threadId = handleSynchronizeSentTextMessage(sent, envelope.timestamp!!)
       }
 
@@ -803,12 +805,12 @@ object SyncMessageProcessor {
   }
 
   @Throws(MmsException::class, BadGroupIdException::class)
-  private fun handleSynchronizeSentMediaMessage(context: Context, sent: Sent, envelopeTimestamp: Long): Long {
+  private fun handleSynchronizeSentMediaMessage(context: Context, sent: Sent, envelopeTimestamp: Long, senderRecipient: Recipient, threadRecipient: Recipient): Long {
     log(envelopeTimestamp, "Synchronize sent media message for " + sent.timestamp!!)
 
     val recipient: Recipient = getSyncMessageDestination(sent)
     val dataMessage: DataMessage = sent.message!!
-    val quote: QuoteModel? = DataMessageProcessor.getValidatedQuote(context, envelopeTimestamp, dataMessage)
+    val quote: QuoteModel? = DataMessageProcessor.getValidatedQuote(context, envelopeTimestamp, dataMessage, senderRecipient, threadRecipient)
     val sticker: Attachment? = DataMessageProcessor.getStickerAttachment(envelopeTimestamp, dataMessage)
     val sharedContacts: List<Contact> = DataMessageProcessor.getContacts(dataMessage)
     val previews: List<LinkPreview> = DataMessageProcessor.getLinkPreviews(dataMessage.preview, dataMessage.body ?: "", false)