diff --git a/requirements/_requirements_base.txt b/requirements/_requirements_base.txt
index 9c9a2d5..a3e3990 100644
--- a/requirements/_requirements_base.txt
+++ b/requirements/_requirements_base.txt
@@ -2,7 +2,7 @@ tqdm>=4.65
 psutil>=5.9.0
 numexpr>=2.8.7
 numpy>=1.26.0,<2.0.0
-opencv-python>=4.9.0.0
+opencv-python>=4.9.0.0,<4.12.0.0  # >=4.12 pulls in numpy2.x
 pillow>=9.4.0,<10.0.0
 scikit-learn>=1.3.0
 fastcluster>=1.2.6