diff --git a/package/x11r7/mcookie/mcookie.c b/package/x11r7/mcookie/mcookie.c
index 902d92fc47..3c38f6f3b3 100644
--- a/package/x11r7/mcookie/mcookie.c
+++ b/package/x11r7/mcookie/mcookie.c
@@ -204,7 +204,7 @@ void MD5Final(unsigned char digest[16], struct MD5Context *ctx)
     MD5Transform(ctx->buf, (uint32 *) ctx->in);
     byteReverse((unsigned char *) ctx->buf, 4);
     memcpy(digest, ctx->buf, 16);
-    memset(ctx, 0, sizeof(ctx));	/* In case it's sensitive */
+    memset(ctx, 0, sizeof(*ctx));	/* In case it's sensitive */
 }
 
 /* The four core functions - F1 is optimized somewhat */