# UNDF: UNDF-2026-000000963
--- a/apps/openmw/mwmechanics/pathgrid.cpp
+++ b/apps/openmw/mwmechanics/pathgrid.cpp
@@ -1,6 +1,7 @@
 #include "pathgrid.hpp"

 #include <algorithm>
+#include <unordered_set>
 #include <list>
 #include <set>

@@ -57,6 +58,7 @@
         int mSCCId = 0;
         size_t mSCCIndex = 0;
         std::vector<size_t> mSCCStack;
+        std::unordered_set<size_t> mSCCOnStack;
         std::vector<std::pair<size_t, size_t>> mSCCPoint; // first is index, second is lowlink

         // v is the pathgrid point index (some call them vertices)
@@ -66,6 +68,7 @@
             mSCCPoint[v].second = mSCCIndex; // lowlink
             mSCCIndex++;
             mSCCStack.push_back(v);
+            mSCCOnStack.insert(v);
             size_t w;

             for (const auto& edge : mGraph[v].edges)
@@ -77,7 +80,7 @@
                     mSCCPoint[v].second = std::min(mSCCPoint[v].second, mSCCPoint[w].second);
                 }
-                else if (std::find(mSCCStack.begin(), mSCCStack.end(), w) != mSCCStack.end())
+                else if (mSCCOnStack.count(w))
                     mSCCPoint[v].second = std::min(mSCCPoint[v].second, mSCCPoint[w].first);
             }

@@ -88,6 +91,7 @@
                 {
                     w = mSCCStack.back();
                     mSCCStack.pop_back();
+                    mSCCOnStack.erase(w);
                     mGraph[w].componentId = mSCCId;
                 } while (w != v);
                 mSCCId++;