diff --git a/package.json b/package.json
index 02cefd0de..2d21fac55 100644
--- a/package.json
+++ b/package.json
@@ -59,7 +59,7 @@
     "yorkie": "2.0.0"
   },
   "dependencies": {
-    "@koa/router": "9.0.0",
+    "@koa/router": "8.0.8",
     "@postlight/mercury-parser": "2.2.0",
     "@sentry/node": "5.15.4",
     "aes-js": "3.1.2",
diff --git a/yarn.lock b/yarn.lock
index db743498a..68b05e8f9 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1218,16 +1218,16 @@
     "@types/yargs" "^15.0.0"
     chalk "^3.0.0"
 
-"@koa/router@9.0.0":
-  version "9.0.0"
-  resolved "https://registry.yarnpkg.com/@koa/router/-/router-9.0.0.tgz#ceec54a20f5e34b19091b4e0c8fea8d00a4a0ad8"
-  integrity sha512-JPi8XHgCrHkc81V7vrwuTJIFM51BNt4WryOd+0t4mCouuT5HpZa/VOzrT0Ts/ksa3b1ZyBHZeARtGObPoMHEdg==
+"@koa/router@8.0.8":
+  version "8.0.8"
+  resolved "https://registry.yarnpkg.com/@koa/router/-/router-8.0.8.tgz#95f32d11373d03d89dcb63fabe9ac6f471095236"
+  integrity sha512-FnT93N4NUehnXr+juupDmG2yfi0JnWdCmNEuIXpCG4TtG+9xvtrLambBH3RclycopVUOEYAim2lydiNBI7IRVg==
   dependencies:
     debug "^4.1.1"
     http-errors "^1.7.3"
     koa-compose "^4.1.0"
     methods "^1.1.2"
-    path-to-regexp "^6.1.0"
+    path-to-regexp "1.x"
     urijs "^1.19.2"
 
 "@mrmlnc/readdir-enhanced@^2.2.1":
@@ -6641,6 +6641,11 @@ is-yarn-global@^0.3.0:
   resolved "https://registry.yarnpkg.com/is-yarn-global/-/is-yarn-global-0.3.0.tgz#d502d3382590ea3004893746754c89139973e232"
   integrity sha512-VjSeb/lHmkoyd8ryPVIKvOCn4D1koMqY+vqyjjUfc3xyKtP4dYOxM44sZrnqQSzSds3xyOrUTLTC9LVCVgLngw==
 
+isarray@0.0.1:
+  version "0.0.1"
+  resolved "https://registry.yarnpkg.com/isarray/-/isarray-0.0.1.tgz#8a18acfca9a8f4177e09abfc6038939b05d1eedf"
+  integrity sha1-ihis/Kmo9Bd+Cav8YDiTmwXR7t8=
+
 isarray@1.0.0, isarray@^1.0.0, isarray@~1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/isarray/-/isarray-1.0.0.tgz#bb935d48582cba168c06834957a54a3e07124f11"
@@ -9015,10 +9020,12 @@ path-to-regexp@0.1.7:
   resolved "https://registry.yarnpkg.com/path-to-regexp/-/path-to-regexp-0.1.7.tgz#df604178005f522f15eb4490e7247a1bfaa67f8c"
   integrity sha1-32BBeABfUi8V60SQ5yR6G/qmf4w=
 
-path-to-regexp@^6.1.0:
-  version "6.1.0"
-  resolved "https://registry.yarnpkg.com/path-to-regexp/-/path-to-regexp-6.1.0.tgz#0b18f88b7a0ce0bfae6a25990c909ab86f512427"
-  integrity sha512-h9DqehX3zZZDCEm+xbfU0ZmwCGFCAAraPJWMXJ4+v32NjZJilVg3k1TcKsRgIb8IQ/izZSaydDc1OhJCZvs2Dw==
+path-to-regexp@1.x:
+  version "1.8.0"
+  resolved "https://registry.yarnpkg.com/path-to-regexp/-/path-to-regexp-1.8.0.tgz#887b3ba9d84393e87a0a0b9f4cb756198b53548a"
+  integrity sha512-n43JRhlUKUAlibEJhPeir1ncUID16QnEjNpwzNdO3Lm4ywrBpBZ5oLD0I6br9evr1Y9JTqwRtAh7JLoOzAQdVA==
+  dependencies:
+    isarray "0.0.1"
 
 path-type@^3.0.0:
   version "3.0.0"