1 files changed, 3 insertions, 0 deletions
diff --git a/core/src/fpdfapi/fpdf_font/fpdf_font.cpp b/core/src/fpdfapi/fpdf_font/fpdf_font.cpp
index 4bec3337b1..72b8adbe20 100644
--- a/core/src/fpdfapi/fpdf_font/fpdf_font.cpp
+++ b/core/src/fpdfapi/fpdf_font/fpdf_font.cpp
@@ -1464,6 +1464,9 @@ void CPDF_TrueTypeFont::LoadGlyphMap()
             && m_pCharNames == NULL) || (m_Flags & PDFFONT_NONSYMBOLIC)) {
         if (!FXFT_Has_Glyph_Names(m_Font.m_Face) && (!m_Font.m_Face->num_charmaps || !m_Font.m_Face->charmaps)) {
             int nStartChar = m_pFontDict->GetInteger(FX_BSTRC("FirstChar"));
+            if(nStartChar < 0 || nStartChar > 255)
+                return;
+
             int charcode = 0;
             for (; charcode < nStartChar; charcode ++) {
                 m_GlyphIndex[charcode] = 0;