Preventing OverflowException when parsing scientific form of numbers. (#17296)

Author: Maximys

src/libraries/Common/src/System/Globalization/FormatProvider.Number.cs

@@ -517,7 +517,19 @@ private static unsafe bool ParseNumber(ref char* str, char* strEnd, NumberStyles
                             {
                                 exp = exp * 10 + (ch - '0');
                                 ch = ++p < strEnd ? *p : '\0';
-                            } while (ch >= '0' && ch <= '9');
+                            } while ((ch >= '0') && (ch <= '9') && (exp < int.MaxValue / 10));
+
+                            if ((ch >= '0') && (ch <= '9'))
+                            {
+                                // We still had remaining characters but bailed early because
+                                // the exponent was going to overflow. If exp is exactly 214748364
+                                // then we can technically handle one more character being 0-9
+                                // but the additional complexity might not be worthwhile.
+
+                                Debug.Assert(exp >= 214748364);
+                                return false;
+                            }
+
                             if (negExp)
                             {
                                 exp = -exp;