diff --git a/src/cc65/scanstrbuf.c b/src/cc65/scanstrbuf.c
index d33f88a25..f55f52a64 100644
--- a/src/cc65/scanstrbuf.c
+++ b/src/cc65/scanstrbuf.c
@@ -185,7 +185,8 @@ int SB_GetSym (StrBuf* B, StrBuf* Ident, const char* SpecialChars)
             SB_AppendChar (Ident, C);
             SB_Skip (B);
             C = SB_Peek (B);
-        } while (IsIdent (C) || IsDigit (C) || strchr (SpecialChars, C) != 0);
+        } while (IsIdent (C) || IsDigit (C) || 
+                 (C != '\0' && strchr (SpecialChars, C) != 0));
         SB_Terminate (Ident);
      	return 1;
     } else {