diff --git a/core/fxcodec/jbig2/JBig2_SddProc.cpp b/core/fxcodec/jbig2/JBig2_SddProc.cpp
index a37e5af..f26850b 100644
--- a/core/fxcodec/jbig2/JBig2_SddProc.cpp
+++ b/core/fxcodec/jbig2/JBig2_SddProc.cpp
@@ -163,7 +163,7 @@
           if (!BS)
             return nullptr;
         } else if (REFAGGNINST == 1) {
-          uint8_t SBNUMSYMS = SDNUMINSYMS + NSYMSDECODED;
+          uint32_t SBNUMSYMS = SDNUMINSYMS + NSYMSDECODED;
           uint32_t IDI;
           IAID->Decode(pArithDecoder, &IDI);
           if (IDI >= SBNUMSYMS)