diff --git a/.github/workflows/psalm.yml b/.github/workflows/psalm.yml
index a64cb3eb..60915c4c 100644
--- a/.github/workflows/psalm.yml
+++ b/.github/workflows/psalm.yml
@@ -16,4 +16,4 @@ jobs:
       - uses: actions/checkout@v2
 
       - name: Psalm – Static Analysis for PHP
-        uses: docker://vimeo/psalm-github-actions
+        uses: docker://vimeo/psalm-github-actions:4.18.1
diff --git a/composer.json b/composer.json
index 8daca80e..38af1231 100644
--- a/composer.json
+++ b/composer.json
@@ -23,7 +23,7 @@
     },
     "require-dev": {
         "phpunit/phpunit": "^8.0|^9.0",
-        "vimeo/psalm": "^4.6"
+        "vimeo/psalm": "4.18.1"
     },
     "autoload": {
         "psr-4": {