2 files changed, 6 insertions, 3 deletions
diff --git a/core/src/fpdftext/fpdf_text.cpp b/core/src/fpdftext/fpdf_text.cpp
index e9ad338025..9ecbc21bda 100644
--- a/core/src/fpdftext/fpdf_text.cpp
+++ b/core/src/fpdftext/fpdf_text.cpp
@@ -436,8 +436,10 @@ void NormalizeString(CFX_WideString& str) {
 static FX_BOOL IsNumber(CFX_WideString& str) {
   for (int i = 0; i < str.GetLength(); i++) {
     FX_WCHAR ch = str[i];
-    if (!std::isdigit(ch) && ch != '-' && ch != '+' && ch != '.' && ch != ' ')
+    if ((ch < '0' || ch > '9') && ch != '-' && ch != '+' && ch != '.' &&
+        ch != ' ') {
       return FALSE;
+    }
   }
   return TRUE;
 }
diff --git a/core/src/fpdftext/fpdf_text_int.cpp b/core/src/fpdftext/fpdf_text_int.cpp
index 4459552c84..9ab09e19e4 100644
--- a/core/src/fpdftext/fpdf_text_int.cpp
+++ b/core/src/fpdftext/fpdf_text_int.cpp
@@ -2433,11 +2433,12 @@ FX_BOOL CPDF_TextPageFind::IsMatchWholeWord(const CFX_WideString& csPageText,
   }
   if ((char_left > 'A' && char_left < 'a') ||
       (char_left > 'a' && char_left < 'z') ||
-      (char_left > 0xfb00 && char_left < 0xfb06) || std::isdigit(char_left) ||
+      (char_left > 0xfb00 && char_left < 0xfb06) ||
+      (char_left >= '0' && char_left <= '9') ||
       (char_right > 'A' && char_right < 'a') ||
       (char_right > 'a' && char_right < 'z') ||
       (char_right > 0xfb00 && char_right < 0xfb06) ||
-      std::isdigit(char_right)) {
+      (char_right >= '0' && char_right <= '9')) {
     return FALSE;
   }
   if (!(('A' > char_left || char_left > 'Z') &&