diff --git a/days/021-024-quart-async/async_cityscape_api/requirements.txt b/days/021-024-quart-async/async_cityscape_api/requirements.txt
index 8d655b2a..0dfcc340 100644
--- a/days/021-024-quart-async/async_cityscape_api/requirements.txt
+++ b/days/021-024-quart-async/async_cityscape_api/requirements.txt
@@ -8,3 +8,4 @@ quart
 aiohttp
 aiodns
 cchardet
+pycares>=4.9.0 # not directly required, pinned by Snyk to avoid a vulnerability