crypt32: Check length of sequence before checking tag.
diff --git a/dlls/crypt32/decode.c b/dlls/crypt32/decode.c
index eb782d3..0d46fe3 100644
--- a/dlls/crypt32/decode.c
+++ b/dlls/crypt32/decode.c
@@ -475,6 +475,11 @@
      cbEncoded, dwFlags, pDecodePara, pvStructInfo, *pcbStructInfo,
      startingPointer);
 
+    if (!cbEncoded)
+    {
+        SetLastError(CRYPT_E_ASN1_EOD);
+        return FALSE;
+    }
     if (pbEncoded[0] == ASN_SEQUENCE)
     {
         DWORD dataLen;