diff --git a/.changeset/curly-adults-leave.md b/.changeset/curly-adults-leave.md
new file mode 100644
index 00000000..18c9f0fd
--- /dev/null
+++ b/.changeset/curly-adults-leave.md
@@ -0,0 +1,5 @@
+---
+"pwned": patch
+---
+
+Update `undici` to v6.21.1 (only matters on Node v18).
diff --git a/package-lock.json b/package-lock.json
index 7ce44d63..fbc0ef3f 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -9963,9 +9963,10 @@
       }
     },
     "node_modules/undici": {
-      "version": "6.19.2",
-      "resolved": "https://registry.npmjs.org/undici/-/undici-6.19.2.tgz",
-      "integrity": "sha512-JfjKqIauur3Q6biAtHJ564e3bWa8VvT+7cSiOJHFbX4Erv6CLGDpg8z+Fmg/1OI/47RA+GI2QZaF48SSaLvyBA==",
+      "version": "6.21.1",
+      "resolved": "https://registry.npmjs.org/undici/-/undici-6.21.1.tgz",
+      "integrity": "sha512-q/1rj5D0/zayJB2FraXdaWxbhWiNKDvu8naDT2dl1yTlvJp4BLtOcp2a5BvgGNQpYYJzau7tf1WgKv3b+7mqpQ==",
+      "license": "MIT",
       "engines": {
         "node": ">=18.17"
       }
@@ -17397,9 +17398,9 @@
       }
     },
     "undici": {
-      "version": "6.19.2",
-      "resolved": "https://registry.npmjs.org/undici/-/undici-6.19.2.tgz",
-      "integrity": "sha512-JfjKqIauur3Q6biAtHJ564e3bWa8VvT+7cSiOJHFbX4Erv6CLGDpg8z+Fmg/1OI/47RA+GI2QZaF48SSaLvyBA=="
+      "version": "6.21.1",
+      "resolved": "https://registry.npmjs.org/undici/-/undici-6.21.1.tgz",
+      "integrity": "sha512-q/1rj5D0/zayJB2FraXdaWxbhWiNKDvu8naDT2dl1yTlvJp4BLtOcp2a5BvgGNQpYYJzau7tf1WgKv3b+7mqpQ=="
     },
     "undici-types": {
       "version": "6.20.0",