diff --git a/Dockerfiles/spack.yaml b/Dockerfiles/spack.yaml
index 5b5440bfe..70f44fca2 100644
--- a/Dockerfiles/spack.yaml
+++ b/Dockerfiles/spack.yaml
@@ -5,7 +5,7 @@ spack:
   specs:
   - boost@1.80.0+log+program_options
   - catch2
-  - cmake@3.27.7
+  - 'cmake@3.20:'
   - eigen@3.4.0
   - gmake
   - hdf5@1.14.3
diff --git a/spack.yaml b/spack.yaml
index 352886770..2d89b4572 100644
--- a/spack.yaml
+++ b/spack.yaml
@@ -5,7 +5,7 @@ spack:
   specs:
   - boost@1.80.0+log+program_options
   - catch2
-  - cmake@3.27.7
+  - 'cmake@3.20:'
   - eigen@3.4.0
   - gmake
   - hdf5@1.14.3