diff --git a/lib/isc/include/isc/url.h b/lib/isc/include/isc/url.h
index d3b935ba97..802beb9135 100644
--- a/lib/isc/include/isc/url.h
+++ b/lib/isc/include/isc/url.h
@@ -49,6 +49,8 @@
 #define HTTP_PARSER_STRICT 1
 #endif
 
+#define URL_MAX_LENGTH 8192
+
 typedef enum {
 	ISC_UF_SCHEMA = 0,
 	ISC_UF_HOST = 1,
diff --git a/lib/isc/url.c b/lib/isc/url.c
index 6d378039a4..0a91eeeaa2 100644
--- a/lib/isc/url.c
+++ b/lib/isc/url.c
@@ -549,7 +549,7 @@ isc_url_parse(const char *buf, size_t buflen, bool is_connect,
 	int found_at = 0;
 	const char *p = NULL;
 
-	if (buflen == 0 || buflen > UINT16_MAX) {
+	if (buflen == 0 || buflen > URL_MAX_LENGTH) {
 		return ISC_R_RANGE;
 	}
 
diff --git a/tests/isc/url_test.c b/tests/isc/url_test.c
index 24f0dd2b63..827342147a 100644
--- a/tests/isc/url_test.c
+++ b/tests/isc/url_test.c
@@ -118,11 +118,11 @@ ISC_RUN_TEST_IMPL(parse) {
 	assert_int_equal(9, up.field_data[ISC_UF_USERINFO].len);
 
 	/*
-	 * Test the maximum accepted buffer length (UINT16_MAX). A path of
-	 * exactly UINT16_MAX bytes also drives ISC_UF_PATH.len to its
-	 * uint16_t maximum without overflowing.
+	 * Test the maximum accepted buffer length (URL_MAX_LENGTH). A path of
+	 * exactly URL_MAX_LENGTH bytes also drives ISC_UF_PATH.len to its
+	 * maximum without overflowing.
 	 */
-	size_t max_len = UINT16_MAX;
+	size_t max_len = URL_MAX_LENGTH;
 	char *max_buf = isc_mem_get(isc_g_mctx, max_len);
 	memset(max_buf, 'a', max_len);
 	max_buf[0] = '/';
@@ -130,14 +130,14 @@ ISC_RUN_TEST_IMPL(parse) {
 	isc_mem_put(isc_g_mctx, max_buf, max_len);
 	assert_int_equal(ISC_R_SUCCESS, result);
 	assert_int_equal(0, up.field_data[ISC_UF_PATH].off);
-	assert_int_equal(UINT16_MAX, up.field_data[ISC_UF_PATH].len);
+	assert_int_equal(URL_MAX_LENGTH, up.field_data[ISC_UF_PATH].len);
 
-	/* Test a too big buffer (UINT16_MAX + 1). */
-	size_t buf_len = UINT16_MAX + 2;
+	/* Test a too big buffer (URL_MAX_LENGTH + 1). */
+	size_t buf_len = URL_MAX_LENGTH + 2;
 	char *buf = isc_mem_get(isc_g_mctx, buf_len);
 	memset(buf, 'a', buf_len);
 	buf[0] = '/';
-	result = isc_url_parse(buf, UINT16_MAX + 1, false, &up);
+	result = isc_url_parse(buf, URL_MAX_LENGTH + 1, false, &up);
 	isc_mem_put(isc_g_mctx, buf, buf_len);
 	assert_int_equal(ISC_R_RANGE, result);
 }