diff -ruN qtbase-opensource-src-5.7.1-orig/src/gui/painting/qfixed_p.h qtbase-opensource-src-5.7.1/src/gui/painting/qfixed_p.h
--- qtbase-opensource-src-5.7.1-orig/src/gui/painting/qfixed_p.h	2016-12-01 02:17:04.000000000 -0600
+++ qtbase-opensource-src-5.7.1/src/gui/painting/qfixed_p.h	2023-06-04 10:03:49.000000000 -0500
@@ -53,6 +53,7 @@
 
 #include "QtCore/qdebug.h"
 #include "QtCore/qpoint.h"
+#include <QtCore/private/qnumeric_p.h>
 #include "QtCore/qsize.h"
 
 QT_BEGIN_NAMESPACE
@@ -181,6 +182,14 @@
 Q_DECL_CONSTEXPR inline bool operator>(const QFixed &f, int i) { return f.value() > i * 64; }
 Q_DECL_CONSTEXPR inline bool operator>(int i, const QFixed &f) { return i * 64 > f.value(); }
 
+inline bool qAddOverflow(QFixed v1, QFixed v2, QFixed *r)
+{
+    int val;
+    bool result = add_overflow(v1.value(), v2.value(), &val);
+    r->setValue(val);
+    return result;
+}
+
 #ifndef QT_NO_DEBUG_STREAM
 inline QDebug &operator<<(QDebug &dbg, const QFixed &f)
 { return dbg << f.toReal(); }
diff -ruN qtbase-opensource-src-5.7.1-orig/src/gui/text/qtextlayout.cpp qtbase-opensource-src-5.7.1/src/gui/text/qtextlayout.cpp
--- qtbase-opensource-src-5.7.1-orig/src/gui/text/qtextlayout.cpp	2016-12-01 02:17:04.000000000 -0600
+++ qtbase-opensource-src-5.7.1/src/gui/text/qtextlayout.cpp	2023-06-04 10:06:20.000000000 -0500
@@ -2036,11 +2036,14 @@
         eng->maxWidth = qMax(eng->maxWidth, line.textWidth);
     } else {
         eng->minWidth = qMax(eng->minWidth, lbh.minw);
-        eng->maxWidth += line.textWidth;
+        if (qAddOverflow(eng->maxWidth, line.textWidth, &eng->maxWidth))
+            eng->maxWidth = QFIXED_MAX;
     }
 
-    if (line.textWidth > 0 && item < eng->layoutData->items.size())
-        eng->maxWidth += lbh.spaceData.textWidth;
+    if (line.textWidth > 0 && item < eng->layoutData->items.size()) {
+        if (qAddOverflow(eng->maxWidth, lbh.spaceData.textWidth, &eng->maxWidth))
+            eng->maxWidth = QFIXED_MAX;
+    }
     if (eng->option.flags() & QTextOption::IncludeTrailingSpaces)
         line.textWidth += lbh.spaceData.textWidth;
     if (lbh.spaceData.length) {