diff --git a/config/http_config.go b/config/http_config.go
index 69c0b671..c07f696a 100644
--- a/config/http_config.go
+++ b/config/http_config.go
@@ -846,12 +846,12 @@ func (c *TLSConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
 
 // readCertAndKey reads the cert and key files from the disk.
 func readCertAndKey(certFile, keyFile string) ([]byte, []byte, error) {
-	certData, err := ioutil.ReadFile(certFile)
+	certData, err := os.ReadFile(certFile)
 	if err != nil {
 		return nil, nil, err
 	}
 
-	keyData, err := ioutil.ReadFile(keyFile)
+	keyData, err := os.ReadFile(keyFile)
 	if err != nil {
 		return nil, nil, err
 	}
diff --git a/config/http_config_test.go b/config/http_config_test.go
index 036fd2dc..89594cd6 100644
--- a/config/http_config_test.go
+++ b/config/http_config_test.go
@@ -1536,7 +1536,7 @@ func TestOAuth2Proxy(t *testing.T) {
 func TestModifyTLSCertificates(t *testing.T) {
 	bs := getCertificateBlobs(t)
 
-	tmpDir, err := ioutil.TempDir("", "modifytlscertificates")
+	tmpDir, err := os.MkdirTemp("", "modifytlscertificates")
 	if err != nil {
 		t.Fatal("Failed to create tmp dir", err)
 	}
@@ -1632,7 +1632,7 @@ func TestModifyTLSCertificates(t *testing.T) {
 				t.Fatalf("Expected no error, got %q", err)
 			}
 
-			b, err := ioutil.ReadAll(r.Body)
+			b, err := io.ReadAll(r.Body)
 			r.Body.Close()
 			if err != nil {
 				t.Errorf("Can't read the server response body")