diff --git a/build.gradle.kts b/build.gradle.kts
index b36fcfde1..9045b07ce 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -6,7 +6,7 @@ val assertjVersion = "3.27.4"
 val kotlinLoggingVersion = "3.0.5"
 val logbackVersion = "1.5.18"
 val nimbusSdkVersion = "11.28"
-val mockWebServerVersion = "4.12.0"
+val mockWebServerVersion = "5.1.0"
 val jacksonVersion = "2.20.0"
 val nettyVersion = "4.2.5.Final"
 val junitJupiterVersion = "5.13.4"
diff --git a/src/main/kotlin/no/nav/security/mock/oauth2/debugger/Client.kt b/src/main/kotlin/no/nav/security/mock/oauth2/debugger/Client.kt
index ac82cba46..99c38993d 100644
--- a/src/main/kotlin/no/nav/security/mock/oauth2/debugger/Client.kt
+++ b/src/main/kotlin/no/nav/security/mock/oauth2/debugger/Client.kt
@@ -10,7 +10,6 @@ import okhttp3.MediaType.Companion.toMediaType
 import okhttp3.OkHttpClient
 import okhttp3.Request
 import okhttp3.RequestBody.Companion.toRequestBody
-import okhttp3.internal.toHostHeader
 import java.net.URLEncoder
 import java.nio.charset.StandardCharsets
 import javax.net.ssl.SSLContext
@@ -44,6 +43,15 @@ internal class TokenRequest(
             } +
             "\n\n$body"
 
+    private fun HttpUrl.toHostHeader(includeDefaultPort: Boolean = false): String {
+        val host = if (":" in host) "[$host]" else host
+        return if (includeDefaultPort || port != HttpUrl.defaultPort(scheme)) {
+            "$host:$port"
+        } else {
+            host
+        }
+    }
+
     private fun Map<String, String>.toKeyValueString(entrySeparator: String): String =
         this
             .map { "${it.key}=${it.value}" }