diff --git a/BUILDING.md b/BUILDING.md
index 6a5ba91761..c9baa9ac48 100644
--- a/BUILDING.md
+++ b/BUILDING.md
@@ -349,7 +349,7 @@ same version that our continuous builds use.
 
 ```
 cd <your chosen parent folder for the emscripten SDK>
-curl -L https://github.com/emscripten-core/emsdk/archive/refs/tags/3.1.5.zip > emsdk.zip
+curl -L https://github.com/emscripten-core/emsdk/archive/refs/tags/3.1.9.zip > emsdk.zip
 unzip emsdk.zip ; mv emsdk-* emsdk ; cd emsdk
 python ./emsdk.py install latest
 python ./emsdk.py activate latest
diff --git a/build/web/ci-common.sh b/build/web/ci-common.sh
index 9bca22cf3a..00e342a891 100755
--- a/build/web/ci-common.sh
+++ b/build/web/ci-common.sh
@@ -17,7 +17,7 @@ export PATH="$PWD:$PATH"
 # npm install -g typescript
 
 # Install emscripten.
-curl -L https://github.com/emscripten-core/emsdk/archive/refs/tags/3.1.5.zip > emsdk.zip
+curl -L https://github.com/emscripten-core/emsdk/archive/refs/tags/3.1.9.zip > emsdk.zip
 unzip emsdk.zip ; mv emsdk-* emsdk ; cd emsdk
 ./emsdk install latest
 ./emsdk activate latest