diff --git a/packages/backend/server/package.json b/packages/backend/server/package.json
index 706f86610..f7ec17565 100644
--- a/packages/backend/server/package.json
+++ b/packages/backend/server/package.json
@@ -145,7 +145,7 @@
     "@types/react": "^19.0.1",
     "@types/react-dom": "^19.0.2",
     "@types/semver": "^7.5.8",
-    "@types/sinon": "^17.0.3",
+    "@types/sinon": "^21.0.0",
     "@types/supertest": "^6.0.2",
     "ava": "^6.4.0",
     "c8": "^10.1.3",
diff --git a/yarn.lock b/yarn.lock
index b9db99249..3b3a88caa 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1020,7 +1020,7 @@ __metadata:
     "@types/react": "npm:^19.0.1"
     "@types/react-dom": "npm:^19.0.2"
     "@types/semver": "npm:^7.5.8"
-    "@types/sinon": "npm:^17.0.3"
+    "@types/sinon": "npm:^21.0.0"
     "@types/supertest": "npm:^6.0.2"
     ai: "npm:^5.0.118"
     ava: "npm:^6.4.0"
@@ -17619,12 +17619,12 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@types/sinon@npm:^17.0.3":
-  version: 17.0.4
-  resolution: "@types/sinon@npm:17.0.4"
+"@types/sinon@npm:^21.0.0":
+  version: 21.0.0
+  resolution: "@types/sinon@npm:21.0.0"
   dependencies:
     "@types/sinonjs__fake-timers": "npm:*"
-  checksum: 10/286c34e66e3573673ba59a332ac81189e20dd591c5c5360c8ff3ed83a59a60bdb1d4c8f13ab8863a4d5ce636282e4b11c640b87f398663eee152988ca09b1933
+  checksum: 10/3add134347bd2b96c4d136bc41108553d31f2b4ca44c118ae69832d8bd9896d9faec07c08ba933cd25ba8699503303e8743d84fc8f5317c16b5cfb8245d0bc29
   languageName: node
   linkType: hard