diff --git a/requirements.txt b/requirements.txt
index b1a3a5f..9d09191 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -85,7 +85,7 @@ plac==1.1.3
 preshed==3.0.2
 prometheus-client==0.7.1
 prompt-toolkit==3.0.2
-protobuf==3.11.2
+protobuf==3.18.3
 ptyprocess==0.6.0
 pyasn1==0.4.8
 pyasn1-modules==0.2.7
diff --git a/sudoku-solver/requirements.txt b/sudoku-solver/requirements.txt
index 51b52f4..b99c7a9 100644
--- a/sudoku-solver/requirements.txt
+++ b/sudoku-solver/requirements.txt
@@ -81,7 +81,7 @@ plac==1.1.3
 preshed==3.0.2
 prometheus-client==0.7.1
 prompt-toolkit==3.0.2
-protobuf==3.11.2
+protobuf==3.18.3
 ptyprocess==0.6.0
 pyasn1==0.4.8
 pyasn1-modules==0.2.7