diff --git a/src/main/java/org/apache/commons/cli/help/TextHelpAppendable.java b/src/main/java/org/apache/commons/cli/help/TextHelpAppendable.java
index 14c90c7c2..2b053106c 100644
--- a/src/main/java/org/apache/commons/cli/help/TextHelpAppendable.java
+++ b/src/main/java/org/apache/commons/cli/help/TextHelpAppendable.java
@@ -76,19 +76,22 @@ public static int indexOfWrap(final CharSequence text, final int width, final in
         if (width < 1) {
             throw new IllegalArgumentException("Width must be greater than 0");
         }
+        // width can be Integer.MAX_VALUE (TextStyle.UNSET_MAX_WIDTH), so keep the wrap boundary in a long;
+        // startPos + width as an int overflows to a negative value and yields a negative wrap index.
+        final long end = (long) startPos + width;
         // handle case of width > text.
         // the line ends before the max wrap pos or a new line char found
-        int limit = Math.min(startPos + width, text.length());
+        int limit = (int) Math.min(end, text.length());
         for (int idx = startPos; idx < limit; idx++) {
             if (BREAK_CHAR_SET.contains(text.charAt(idx))) {
                 return idx;
             }
         }
-        if (startPos + width >= text.length()) {
+        if (end >= text.length()) {
             return text.length();
         }
 
-        limit = Math.min(startPos + width, text.length() - 1);
+        limit = (int) Math.min(end, text.length() - 1);
         int pos;
         // look for the last whitespace character before limit
         for (pos = limit; pos >= startPos; --pos) {
diff --git a/src/test/java/org/apache/commons/cli/help/TextHelpAppendableTest.java b/src/test/java/org/apache/commons/cli/help/TextHelpAppendableTest.java
index 9c58427d5..182cf50fc 100644
--- a/src/test/java/org/apache/commons/cli/help/TextHelpAppendableTest.java
+++ b/src/test/java/org/apache/commons/cli/help/TextHelpAppendableTest.java
@@ -280,6 +280,10 @@ void testindexOfWrapPos() {
 
         assertThrows(IllegalArgumentException.class, () -> TextHelpAppendable.indexOfWrap("", 0, 0));
         assertEquals(3, TextHelpAppendable.indexOfWrap("Hello", 4, 0));
+
+        // startPos + width must not overflow when width is TextStyle.UNSET_MAX_WIDTH
+        assertEquals(30, TextHelpAppendable.indexOfWrap(testString, TextStyle.UNSET_MAX_WIDTH, 0), "did not find break character with unbounded width");
+        assertEquals(testString.length(), TextHelpAppendable.indexOfWrap(testString, TextStyle.UNSET_MAX_WIDTH, 31), "overflow produced a negative wrap index");
     }
 
     @ParameterizedTest