diff --git a/library/ssl_cookie.c b/library/ssl_cookie.c
index 7e0c573..786af6d 100644
--- a/library/ssl_cookie.c
+++ b/library/ssl_cookie.c
@@ -98,7 +98,7 @@
     mbedtls_md_free( &ctx->hmac_ctx );
 
 #if defined(MBEDTLS_THREADING_C)
-    mbedtls_mutex_init( &ctx->mutex );
+    mbedtls_mutex_free( &ctx->mutex );
 #endif
 
     mbedtls_zeroize( ctx, sizeof( mbedtls_ssl_cookie_ctx ) );