diff --git a/grafast/grafserv/package.json b/grafast/grafserv/package.json
index abca11fec3..9f7c732fe5 100644
--- a/grafast/grafserv/package.json
+++ b/grafast/grafserv/package.json
@@ -153,7 +153,7 @@
     "@whatwg-node/fetch": "^0.10.8",
     "@whatwg-node/server": "^0.10.10",
     "express": "^4.21.2",
-    "fastify": "^5.8.1",
+    "fastify": "^5.8.3",
     "grafast": "workspace:^",
     "graphql": "^16.9.0",
     "graphql-http": "^1.22.4",
diff --git a/graphile-build/graphile-build-pg/package.json b/graphile-build/graphile-build-pg/package.json
index 8ed030a208..23a85b0bc3 100644
--- a/graphile-build/graphile-build-pg/package.json
+++ b/graphile-build/graphile-build-pg/package.json
@@ -108,7 +108,7 @@
     "@types/jsonwebtoken": "^9.0.10",
     "chalk": "^4.1.2",
     "express": "^4.21.2",
-    "fastify": "^5.8.1",
+    "fastify": "^5.8.3",
     "grafast": "workspace:^",
     "grafserv": "workspace:^",
     "graphile-export": "workspace:^",
diff --git a/yarn.lock b/yarn.lock
index 9dd6305359..0bc3261527 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -13808,9 +13808,9 @@ __metadata:
   languageName: node
   linkType: hard
 
-"fastify@npm:^5.8.1":
-  version: 5.8.2
-  resolution: "fastify@npm:5.8.2"
+"fastify@npm:^5.8.3":
+  version: 5.8.4
+  resolution: "fastify@npm:5.8.4"
   dependencies:
     "@fastify/ajv-compiler": "npm:^4.0.5"
     "@fastify/error": "npm:^4.0.0"
@@ -13827,7 +13827,7 @@ __metadata:
     secure-json-parse: "npm:^4.0.0"
     semver: "npm:^7.6.0"
     toad-cache: "npm:^3.7.0"
-  checksum: 10/5250ad830dbc6227e950c977ed3a0c69643aaa7812129a426098c90ace733b81695197b6c878228deacaae338aa8e827b56345784a5a4e0a495e4b69ac84c26a
+  checksum: 10/979e8d980aba673b8801e898a322df4ab594819666f74441c8aebc6cfc88eece72f545415f3945da8a5dbb831995cc88ea4a2bade448fe4570a360bc9cb4cab6
   languageName: node
   linkType: hard
 
@@ -14708,7 +14708,7 @@ __metadata:
     debug: "npm:^4.4.3"
     eventemitter3: "npm:^5.0.1"
     express: "npm:^4.21.2"
-    fastify: "npm:^5.8.1"
+    fastify: "npm:^5.8.3"
     grafast: "workspace:^"
     graphile-config: "workspace:^"
     graphql: "npm:^16.9.0"
@@ -14773,7 +14773,7 @@ __metadata:
     chalk: "npm:^4.1.2"
     debug: "npm:^4.4.3"
     express: "npm:^4.21.2"
-    fastify: "npm:^5.8.1"
+    fastify: "npm:^5.8.3"
     grafast: "workspace:^"
     grafserv: "workspace:^"
     graphile-config: "workspace:^"