diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index a25e1d38..233d51b3 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -28,7 +28,7 @@ jobs:
           # Note: Specifying the version of valgrind is not supported.
           # cargo-watch is supported by cargo-binstall (through quickinstall)
           - cargo-hack,cargo-llvm-cov,cargo-minimal-versions,parse-changelog,cargo-udeps,cargo-valgrind,cross,nextest,protoc,shellcheck,shfmt,valgrind,wasm-pack,wasmtime,mdbook,mdbook-linkcheck,cargo-watch
-          - cargo-hack@0.5.18,cargo-llvm-cov@0.5.0,cargo-minimal-versions@0.1.5,parse-changelog@0.5.1,cargo-udeps@0.1.32,cargo-valgrind@2.1.0,cross@0.2.4,nextest@0.9.11,protoc@3.21.5,shellcheck@0.8.0,shfmt@3.5.1,wasm-pack@0.10.3,wasmtime@0.40.1,mdbook@0.4.21,mdbook-linkcheck@0.7.6,cargo-watch@8.1.1
+          - cargo-hack@0.5.18,cargo-llvm-cov@0.5.0,cargo-minimal-versions@0.1.5,parse-changelog@0.5.1,cargo-udeps@0.1.32,cargo-valgrind@2.1.0,cross@0.2.4,nextest@0.9.11,protoc@3.21.6,shellcheck@0.8.0,shfmt@3.5.1,wasm-pack@0.10.3,wasmtime@0.40.1,mdbook@0.4.21,mdbook-linkcheck@0.7.6,cargo-watch@8.1.1
           # Nextest supports basic version ranges as well
           - nextest@0.9
         include:
diff --git a/CHANGELOG.md b/CHANGELOG.md
index bbf0a348..d3e33572 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,8 @@ Note: In this file, do not use the hard wrap in the middle of a sentence for com
 
 ## [Unreleased]
 
+- Update `protoc@latest` to 3.21.6.
+
 ## [1.13.0] - 2022-09-10
 
 - Avoid using sudo on `protoc` installation.
diff --git a/main.sh b/main.sh
index c3f897b2..646f9033 100755
--- a/main.sh
+++ b/main.sh
@@ -277,7 +277,7 @@ for tool in "${tools[@]}"; do
             ;;
         protoc)
             # https://github.com/protocolbuffers/protobuf/releases
-            latest_version="3.21.5"
+            latest_version="3.21.6"
             repo="protocolbuffers/protobuf"
             case "${version}" in
                 latest) version="${latest_version}" ;;