diff --git a/pyproject.toml b/pyproject.toml
index 5f25ecf8..6dccdf51 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -25,7 +25,7 @@ classifiers = [
   "Programming Language :: Python :: 3.12",
 ]
 dependencies = [
-  "flask>=2.0,<4.0",
+  "flask>=2.0,<4.0,!=3.1.1",
   "click>=7.0,<9.0",
   "watchdog>=1.0.0",
   "gunicorn>=22.0.0; platform_system!='Windows'",