diff --git a/package.json b/package.json
index 85f8a9d..10d338d 100644
--- a/package.json
+++ b/package.json
@@ -87,7 +87,7 @@
     "babel-plugin-unassert": "3.2.0",
     "babel-preset-power-assert": "3.0.0",
     "benchmark": "2.1.4",
-    "c8": "8.0.1",
+    "c8": "9.0.0",
     "esdoc": "1.1.0",
     "esdoc-inject-script-plugin": "1.0.0",
     "esdoc-inject-style-plugin": "1.0.0",
diff --git a/yarn.lock b/yarn.lock
index f5dba11..a03005d 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -3516,19 +3516,18 @@ bundle-name@^3.0.0:
   dependencies:
     run-applescript "^5.0.0"
 
-c8@8.0.1:
-  version "8.0.1"
-  resolved "https://registry.yarnpkg.com/c8/-/c8-8.0.1.tgz#bafd60be680e66c5530ee69f621e45b1364af9fd"
-  integrity sha512-EINpopxZNH1mETuI0DzRA4MZpAUH+IFiRhnmFD3vFr3vdrgxqi3VfE3KL0AIL+zDq8rC9bZqwM/VDmmoe04y7w==
+c8@9.0.0:
+  version "9.0.0"
+  resolved "https://registry.yarnpkg.com/c8/-/c8-9.0.0.tgz#96f135754bbfc9fceb3c118970dcfd4a158de59d"
+  integrity sha512-nFJhU2Cz6Frh2awk3IW7wwk3wx27/U2v8ojQCHGc1GWTCHS6aMu4lal327/ZnnYj7oSThGF1X3qUP1yzAJBcOQ==
   dependencies:
     "@bcoe/v8-coverage" "^0.2.3"
     "@istanbuljs/schema" "^0.1.3"
     find-up "^5.0.0"
-    foreground-child "^2.0.0"
+    foreground-child "^3.1.1"
     istanbul-lib-coverage "^3.2.0"
     istanbul-lib-report "^3.0.1"
     istanbul-reports "^3.1.6"
-    rimraf "^3.0.2"
     test-exclude "^6.0.0"
     v8-to-istanbul "^9.0.0"
     yargs "^17.7.2"
@@ -5826,13 +5825,13 @@ flatted@^3.1.0:
   resolved "https://registry.yarnpkg.com/flatted/-/flatted-3.2.2.tgz#64bfed5cb68fe3ca78b3eb214ad97b63bedce561"
   integrity sha512-JaTY/wtrcSyvXJl4IMFHPKyFur1sE9AUqc0QnhOaJ0CxHtAoIV8pYDzeEfAaNEtGkOfq4gr3LBFmdXW5mOQFnA==
 
-foreground-child@^2.0.0:
-  version "2.0.0"
-  resolved "https://registry.yarnpkg.com/foreground-child/-/foreground-child-2.0.0.tgz#71b32800c9f15aa8f2f83f4a6bd9bff35d861a53"
-  integrity sha512-dCIq9FpEcyQyXKCkyzmlPTFNgrCzPudOe+mhvJU5zAtlBnGVy2yKxtfsxK2tQBThwq225jcvBjpw1Gr40uzZCA==
+foreground-child@^3.1.1:
+  version "3.1.1"
+  resolved "https://registry.yarnpkg.com/foreground-child/-/foreground-child-3.1.1.tgz#1d173e776d75d2772fed08efe4a0de1ea1b12d0d"
+  integrity sha512-TMKDUnIte6bfb5nWv7V/caI169OHgvwjb7V4WkeUvbQQdjr5rWKqHFiKWb/fcOwB+CzBT+qbWjvj+DVwRskpIg==
   dependencies:
     cross-spawn "^7.0.0"
-    signal-exit "^3.0.2"
+    signal-exit "^4.0.1"
 
 forever-agent@~0.6.1:
   version "0.6.1"