diff --git a/src/fccache.c b/src/fccache.c
index d865266..2d4a437 100644
--- a/src/fccache.c
+++ b/src/fccache.c
@@ -1167,7 +1167,7 @@ static void MD5Final(unsigned char digest[16], struct MD5Context *ctx)
     MD5Transform(ctx->buf, (FcChar32 *) 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 */
 }