From da61dc7eba9ce4708cb18bc2a6b72ade22e2f8b4 Mon Sep 17 00:00:00 2001
From: Tom Rebbert <109624508+trebbert-lutron@users.noreply.github.com>
Date: Fri, 19 Sep 2025 16:35:26 -0600
Subject: [PATCH] [mle] avoid overwriting parent candidate during child ID
 request phase (#11953)

---
 src/core/thread/mle.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/core/thread/mle.cpp b/src/core/thread/mle.cpp
index 71ee8d0e2..30d7d66a9 100644
--- a/src/core/thread/mle.cpp
+++ b/src/core/thread/mle.cpp
@@ -5085,6 +5085,8 @@ void Mle::Attacher::HandleParentResponse(RxInfo &aRxInfo)
 
     Log(kMessageReceive, kTypeParentResponse, aRxInfo.mMessageInfo.GetPeerAddr(), sourceAddress);
 
+    VerifyOrExit(mState != kStateChildIdRequest, error = kErrorInvalidState);
+
     SuccessOrExit(error = aRxInfo.mMessage.ReadVersionTlv(version));
 
     SuccessOrExit(error = aRxInfo.mMessage.ReadAndMatchResponseTlvWith(mParentRequestChallenge));