diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e3b55c400f2..2cac4eab0b3 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -194,10 +194,12 @@ jobs:
           Write-Host "PowerShell version $($PSVersionTable.PSVersion.ToString())"
 
       - name: Using vcpkg with MSBuild
+        shell: bash
         run: |
-          Set-Location "$env:VCPKG_INSTALLATION_ROOT"
-          Add-Content -Path "triplets\x64-windows.cmake" -Value "set(VCPKG_BUILD_TYPE release)"
-          Add-Content -Path "triplets\x64-windows-static.cmake" -Value "set(VCPKG_BUILD_TYPE release)"
+          echo "set(VCPKG_BUILD_TYPE release)" >> "${VCPKG_INSTALLATION_ROOT}/triplets/x64-windows.cmake"
+          echo "set(VCPKG_BUILD_TYPE release)" >> "${VCPKG_INSTALLATION_ROOT}/triplets/x64-windows-static.cmake"
+          # Workaround for libevent, which requires CMake 3.1 but is incompatible with CMake >= 4.0.
+          sed -i '1s/^/set(ENV{CMAKE_POLICY_VERSION_MINIMUM} 3.5)\n/' "${VCPKG_INSTALLATION_ROOT}/scripts/ports.cmake"
 
       - name: vcpkg tools cache
         uses: actions/cache@v4