diff --git a/blockchain/all_challenges/2019/de1ctf/EasyEOS/backend/package.json b/blockchain/all_challenges/2019/de1ctf/EasyEOS/backend/package.json
index c8d6a5d..e0934d1 100644
--- a/blockchain/all_challenges/2019/de1ctf/EasyEOS/backend/package.json
+++ b/blockchain/all_challenges/2019/de1ctf/EasyEOS/backend/package.json
@@ -12,7 +12,7 @@
   "dependencies": {
     "dotenv": "^8.0.0",
     "eosjs": "^20.0.0",
-    "node-fetch": "^2.6.1",
+    "node-fetch": "^3.1.1",
     "nodemailer": "^6.2.1"
   },
   "devDependencies": {
diff --git a/blockchain/all_challenges/2019/de1ctf/EasyEOS/backend/yarn.lock b/blockchain/all_challenges/2019/de1ctf/EasyEOS/backend/yarn.lock
index ed0bc0e..bc60c44 100644
--- a/blockchain/all_challenges/2019/de1ctf/EasyEOS/backend/yarn.lock
+++ b/blockchain/all_challenges/2019/de1ctf/EasyEOS/backend/yarn.lock
@@ -161,6 +161,11 @@ cross-spawn@^6.0.5:
     shebang-command "^1.2.0"
     which "^1.2.9"
 
+data-uri-to-buffer@^4.0.0:
+  version "4.0.0"
+  resolved "https://registry.yarnpkg.com/data-uri-to-buffer/-/data-uri-to-buffer-4.0.0.tgz#b5db46aea50f6176428ac05b73be39a57701a64b"
+  integrity sha512-Vr3mLBA8qWmcuschSLAOogKgQ/Jwxulv3RNE4FXnYWRGujzrRWQI4m12fQqRkwX06C0KanhLr4hK+GydchZsaA==
+
 define-properties@^1.1.2:
   version "1.1.3"
   resolved "https://registry.yarnpkg.com/define-properties/-/define-properties-1.1.3.tgz#cf88da6cbee26fe6db7094f61d870cbd84cee9f1"
@@ -245,6 +250,21 @@ evp_bytestokey@^1.0.3:
     md5.js "^1.3.4"
     safe-buffer "^5.1.1"
 
+fetch-blob@^3.1.2, fetch-blob@^3.1.3:
+  version "3.1.4"
+  resolved "https://registry.yarnpkg.com/fetch-blob/-/fetch-blob-3.1.4.tgz#e8c6567f80ad7fc22fd302e7dcb72bafde9c1717"
+  integrity sha512-Eq5Xv5+VlSrYWEqKrusxY1C3Hm/hjeAsCGVG3ft7pZahlUAChpGZT/Ms1WmSLnEAisEXszjzu/s+ce6HZB2VHA==
+  dependencies:
+    node-domexception "^1.0.0"
+    web-streams-polyfill "^3.0.3"
+
+formdata-polyfill@^4.0.10:
+  version "4.0.10"
+  resolved "https://registry.yarnpkg.com/formdata-polyfill/-/formdata-polyfill-4.0.10.tgz#24807c31c9d402e002ab3d8c720144ceb8848423"
+  integrity sha512-buewHzMvYL29jdeQTVILecSaZKnt/RJWjoZCF5OW60Z67/GmSLBkOFM7qh1PI3zFNtJbaZL5eQu1vLfazOwj4g==
+  dependencies:
+    fetch-blob "^3.1.2"
+
 function-bind@^1.0.2, function-bind@^1.1.1:
   version "1.1.1"
   resolved "https://registry.yarnpkg.com/function-bind/-/function-bind-1.1.1.tgz#a56899d3ea3c9bab874bb9773b7c5ede92f4895d"
@@ -375,10 +395,19 @@ nice-try@^1.0.4:
   resolved "https://registry.yarnpkg.com/nice-try/-/nice-try-1.0.5.tgz#a3378a7696ce7d223e88fc9b764bd7ef1089e366"
   integrity sha512-1nh45deeb5olNY7eX82BkPO7SSxR5SSYJiPTrTdFUVYwAl8CKMA5N9PjTYkHiRjisVcxcQ1HXdLhx2qxxJzLNQ==
 
-node-fetch@^2.6.1:
-  version "2.6.1"
-  resolved "https://registry.yarnpkg.com/node-fetch/-/node-fetch-2.6.1.tgz#045bd323631f76ed2e2b55573394416b639a0052"
-  integrity sha512-V4aYg89jEoVRxRb2fJdAg8FHvI7cEyYdVAh94HH0UIK8oJxUfkjlDQN9RbMx+bEjP7+ggMiFRprSti032Oipxw==
+node-domexception@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/node-domexception/-/node-domexception-1.0.0.tgz#6888db46a1f71c0b76b3f7555016b63fe64766e5"
+  integrity sha512-/jKZoMpw0F8GRwl4/eLROPA3cfcXtLApP0QzLmUT/HuPCZWyB7IY9ZrMeKw2O/nFIqPQB3PVM9aYm0F312AXDQ==
+
+node-fetch@^3.1.1:
+  version "3.1.1"
+  resolved "https://registry.yarnpkg.com/node-fetch/-/node-fetch-3.1.1.tgz#d0d9607e455b3087e3092b821b5b1f1ebf4c2147"
+  integrity sha512-SMk+vKgU77PYotRdWzqZGTZeuFKlsJ0hu4KPviQKkfY+N3vn2MIzr0rvpnYpR8MtB3IEuhlEcuOLbGvLRlA+yg==
+  dependencies:
+    data-uri-to-buffer "^4.0.0"
+    fetch-blob "^3.1.3"
+    formdata-polyfill "^4.0.10"
 
 nodemailer@^6.2.1:
   version "6.2.1"
@@ -586,6 +615,11 @@ validate-npm-package-license@^3.0.1:
     spdx-correct "^3.0.0"
     spdx-expression-parse "^3.0.0"
 
+web-streams-polyfill@^3.0.3:
+  version "3.2.0"
+  resolved "https://registry.yarnpkg.com/web-streams-polyfill/-/web-streams-polyfill-3.2.0.tgz#a6b74026b38e4885869fb5c589e90b95ccfc7965"
+  integrity sha512-EqPmREeOzttaLRm5HS7io98goBgZ7IVz79aDvqjD0kYXLtFZTc0T/U6wHTPKyIjb+MdN7DFIIX6hgdBEpWmfPA==
+
 which@^1.2.9:
   version "1.3.1"
   resolved "https://registry.yarnpkg.com/which/-/which-1.3.1.tgz#a45043d54f5805316da8d62f9f50918d3da70b0a"