--- misc/icu/source/extra/scrptrun/scrptrun.cpp
+++ misc/build/icu/source/extra/scrptrun/scrptrun.cpp
@@ -150,7 +150,11 @@
         // characters above it on the stack will be poped.
         if (pairIndex >= 0) {
             if ((pairIndex & 1) == 0) {
-                parenStack[++parenSP].pairIndex = pairIndex;
+                ++parenSP;
+                int32_t nVecSize = parenStack.size();
+                if (parenSP == nVecSize)
+                    parenStack.resize(nVecSize + 128);
+                parenStack[parenSP].pairIndex = pairIndex;
                 parenStack[parenSP].scriptCode  = scriptCode;
             } else if (parenSP >= 0) {
                 int32_t pi = pairIndex & ~1;
@@ -184,7 +188,14 @@
             // pop it from the stack
             if (pairIndex >= 0 && (pairIndex & 1) != 0 && parenSP >= 0) {
                 parenSP -= 1;
-                startSP -= 1;
+                /* decrement startSP only if it is >= 0,
+                   decrementing it unnecessarily will lead to memory corruption
+                   while processing the above while block.
+                   e.g. startSP = -4 , parenSP = -1
+                */
+                if (startSP >= 0) {
+                    startSP -= 1;
+                }
             }
         } else {
             // if the run broke on a surrogate pair,
--- misc/icu/source/extra/scrptrun/scrptrun.h
+++ misc/build/icu/source/extra/scrptrun/scrptrun.h
@@ -17,6 +17,7 @@
 #include "unicode/utypes.h"
 #include "unicode/uobject.h"
 #include "unicode/uscript.h"
+#include <vector>
 
 struct ScriptRecord
 {
@@ -79,7 +80,7 @@
     int32_t scriptEnd;
     UScriptCode scriptCode;
 
-    ParenStackEntry parenStack[128];
+    std::vector<ParenStackEntry> parenStack;
     int32_t parenSP;
 
     static int8_t highBit(int32_t value);
@@ -133,6 +134,7 @@
     scriptEnd   = charStart;
     scriptCode  = USCRIPT_INVALID_CODE;
     parenSP     = -1;
+    parenStack.resize(128);
 }
 
 inline void ScriptRun::reset(int32_t start, int32_t length)