diff --git a/packages/backend/server/package.json b/packages/backend/server/package.json
index 3349970674..976bbb1512 100644
--- a/packages/backend/server/package.json
+++ b/packages/backend/server/package.json
@@ -147,7 +147,7 @@
     "c8": "^10.1.3",
     "nodemon": "^3.1.7",
     "react-email": "4.0.11",
-    "sinon": "^20.0.0",
+    "sinon": "^21.0.0",
     "supertest": "^7.0.0",
     "why-is-node-running": "^3.2.2"
   },
diff --git a/yarn.lock b/yarn.lock
index 8bf859b646..eea41617aa 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1010,7 +1010,7 @@ __metadata:
     rxjs: "npm:^7.8.1"
     semver: "npm:^7.6.3"
     ses: "npm:^1.10.0"
-    sinon: "npm:^20.0.0"
+    sinon: "npm:^21.0.0"
     socket.io: "npm:^4.8.1"
     stripe: "npm:^17.4.0"
     supertest: "npm:^7.0.0"
@@ -31231,16 +31231,16 @@ __metadata:
   languageName: node
   linkType: hard
 
-"sinon@npm:^20.0.0":
-  version: 20.0.0
-  resolution: "sinon@npm:20.0.0"
+"sinon@npm:^21.0.0":
+  version: 21.0.0
+  resolution: "sinon@npm:21.0.0"
   dependencies:
     "@sinonjs/commons": "npm:^3.0.1"
     "@sinonjs/fake-timers": "npm:^13.0.5"
     "@sinonjs/samsam": "npm:^8.0.1"
     diff: "npm:^7.0.0"
     supports-color: "npm:^7.2.0"
-  checksum: 10/825cb36a58c0510cec03d9bef4fe66a12baf0e0cfdf1600423e3da1e6d57a03fe8161f4859340ea13d4c42e63da1724a260ef4c5ce119dc9ee075ad93b6e8bdd
+  checksum: 10/b460e1cde56fa34ecbebc216522667fa3985444020dc70508177f85d127e6b9a27184c4b3146c575b30ec3091bde508b1373fad306b1e808037a37035e62065d
   languageName: node
   linkType: hard