diff --git a/packages/plugin-hardhat/package.json b/packages/plugin-hardhat/package.json
index f7d7c6158..cc90d6e12 100644
--- a/packages/plugin-hardhat/package.json
+++ b/packages/plugin-hardhat/package.json
@@ -31,7 +31,7 @@
     "promisified": "^0.5.0",
     "proxyquire": "^2.1.3",
     "rimraf": "^5.0.0",
-    "sinon": "^20.0.0"
+    "sinon": "^21.0.0"
   },
   "dependencies": {
     "@openzeppelin/defender-sdk-base-client": "^2.1.0",
diff --git a/yarn.lock b/yarn.lock
index 0a7957714..0290943dd 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -6469,10 +6469,10 @@ signal-exit@^4.0.1, signal-exit@^4.1.0:
   resolved "https://registry.yarnpkg.com/signal-exit/-/signal-exit-4.1.0.tgz#952188c1cbd546070e2dd20d0f41c0ae0530cb04"
   integrity sha512-bzyZ1e88w9O1iNJbKnOlvYTrWPDl46O1bG0D3XInv+9tkPrxrN8jUUTiFlDkkmKWgn1M6CfIA13SuGqOa9Korw==
 
-sinon@^20.0.0:
-  version "20.0.0"
-  resolved "https://registry.yarnpkg.com/sinon/-/sinon-20.0.0.tgz#4b653468735f7152ba694d05498c2b5d024ab006"
-  integrity sha512-+FXOAbdnj94AQIxH0w1v8gzNxkawVvNqE3jUzRLptR71Oykeu2RrQXXl/VQjKay+Qnh73fDt/oDfMo6xMeDQbQ==
+sinon@^21.0.0:
+  version "21.0.0"
+  resolved "https://registry.yarnpkg.com/sinon/-/sinon-21.0.0.tgz#dbda73abc7e6cb803fef3368cfbecbb5936e8a9e"
+  integrity sha512-TOgRcwFPbfGtpqvZw+hyqJDvqfapr1qUlOizROIk4bBLjlsjlB00Pg6wMFXNtJRpu+eCZuVOaLatG7M8105kAw==
   dependencies:
     "@sinonjs/commons" "^3.0.1"
     "@sinonjs/fake-timers" "^13.0.5"