diff --git a/src/md5.c b/src/md5.c
index c4ac4ac..01231b1 100644
--- a/src/md5.c
+++ b/src/md5.c
@@ -148,7 +148,7 @@ void MD5Final(unsigned char digest[16], struct MD5Context *ctx)
     PUT_32BIT_LSB_FIRST(digest + 4, ctx->buf[1]);
     PUT_32BIT_LSB_FIRST(digest + 8, ctx->buf[2]);
     PUT_32BIT_LSB_FIRST(digest + 12, ctx->buf[3]);
-    memset(ctx, 0, sizeof(ctx));	/* In case it's sensitive */
+    memset(ctx, 0, sizeof(*ctx));	/* In case it's sensitive */
 }
 
 #ifndef ASM_MD5