Prevent an OOB access in CPDF_DIBSource::TranslateScanline24bpp

core/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp

Index: core/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp
diff --git a/core/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp b/core/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp
index 7b88e84399d90b15cb81cdda1e1f283bc91aa753..b4671160eff4913615da92fa4ded63e07fc91035 100644
--- a/core/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp
+++ b/core/fpdfapi/fpdf_render/fpdf_render_loadimage.cpp
@@ -918,6 +918,9 @@ void CPDF_DIBSource::TranslateScanline24bpp(uint8_t* dest_scan,
   unsigned int max_data = (1 << m_bpc) - 1;
   if (m_bDefaultDecode) {
     if (m_Family == PDFCS_DEVICERGB || m_Family == PDFCS_CALRGB) {
+      if (m_nComponents != 3)
+        return;
+
       const uint8_t* src_pos = src_scan;
       switch (m_bpc) {
         case 16: