diff --git a/src/unlocker/cert_manager.cpp b/src/unlocker/cert_manager.cpp
index 64a1b16..eee4079 100644
--- a/src/unlocker/cert_manager.cpp
+++ b/src/unlocker/cert_manager.cpp
@@ -191,8 +191,8 @@ SSL_CTX* CertManager::CreateHostContext(const std::string& host)
 
     SSL_CTX_set_alpn_select_cb(
         ctx,
-        [](SSL* ssl, const unsigned char** out, unsigned char* outlen, const unsigned char* in, unsigned int inlen,
-           void* arg) -> int {
+        [](SSL* /*ssl*/, const unsigned char** out, unsigned char* outlen, const unsigned char* in, unsigned int inlen,
+           void* /*arg*/) -> int {
             for (unsigned int i = 0; i < inlen;)
             {
                 unsigned int len = in[i];