From 1e8fd5491bde91fe6daca7d78f217a4d46084a5b Mon Sep 17 00:00:00 2001
From: Hecklezz <tj8@live.com.au>
Date: Thu, 13 Aug 2026 07:13:36 +1000
Subject: [PATCH] [FIRE-35632] Fix LLViewerParcelMgr::writeHighlightSegments
 crashing from writing out of bounds

Merged upstream in SLViewer PR#6126
---
 indra/newview/llviewerparcelmgr.cpp | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/indra/newview/llviewerparcelmgr.cpp b/indra/newview/llviewerparcelmgr.cpp
index a3a34b828d..5cebe6ae4a 100644
--- a/indra/newview/llviewerparcelmgr.cpp
+++ b/indra/newview/llviewerparcelmgr.cpp
@@ -339,6 +339,14 @@ void LLViewerParcelMgr::resetSegments(U8* segments)
 void LLViewerParcelMgr::writeHighlightSegments(F32 west, F32 south, F32 east,
                                                F32 north)
 {
+    if (west < 0 || south < 0 || east < 0 || north < 0)
+    {
+        LL_WARNS() << "Invalid parcel edge coordinates provided to writeHighlightSegments- "
+            << "west: " << west << ", south: " << south << ", east: " << east << ", north: " << north
+            << LL_ENDL;
+        return;
+    }
+
     S32 x, y;
     S32 min_x = ll_round( west / PARCEL_GRID_STEP_METERS );
     S32 max_x = ll_round( east / PARCEL_GRID_STEP_METERS );