diff --git a/eng/Version.Details.xml b/eng/Version.Details.xml
index feea7e754e7..e84d6b39b6e 100644
--- a/eng/Version.Details.xml
+++ b/eng/Version.Details.xml
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Dependencies>
-  <Source Uri="https://github.com/dotnet/dotnet" Mapping="msbuild" Sha="e9593819ed84a62923fe87c8d0958025726934c3" BarId="305927" />
+  <Source Uri="https://github.com/dotnet/dotnet" Mapping="msbuild" Sha="463e0cf2f2b2fb9b136f6440341ff1e7b0a93acf" BarId="322439" />
   <ProductDependencies>
     <!-- Necessary for source-build. This allows the live version of the package to be used by source-build. -->
     <Dependency Name="System.CodeDom" Version="10.0.3">
diff --git a/eng/Versions.props b/eng/Versions.props
index 7fc5b9b9da9..ee21a626c48 100644
--- a/eng/Versions.props
+++ b/eng/Versions.props
@@ -3,7 +3,7 @@
   <Import Project="Version.Details.props" />
 
   <PropertyGroup>
-    <VersionPrefix>18.6.13</VersionPrefix><DotNetFinalVersionKind>release</DotNetFinalVersionKind><!-- Keep next to VersionPrefix to create a conflict in forward-flow -->
+    <VersionPrefix>18.6.14</VersionPrefix><DotNetFinalVersionKind>release</DotNetFinalVersionKind><!-- Keep next to VersionPrefix to create a conflict in forward-flow -->
     <PreReleaseVersionLabel>servicing</PreReleaseVersionLabel>
     <PackageValidationBaselineVersion>18.5.0-preview-26126-01</PackageValidationBaselineVersion>
     <AssemblyVersion>15.1.0.0</AssemblyVersion>
diff --git a/src/Framework/NativeMethods.cs b/src/Framework/NativeMethods.cs
index 46aad3925dc..1b5ce893994 100644
--- a/src/Framework/NativeMethods.cs
+++ b/src/Framework/NativeMethods.cs
@@ -1484,15 +1484,18 @@ internal static List<KeyValuePair<int, SafeProcessHandle>> GetChildProcessIds(in
     /// Internal, optimized GetCurrentDirectory implementation that simply delegates to the native method
     /// </summary>
     /// <returns></returns>
-    internal static unsafe string GetCurrentDirectory()
+    internal static string GetCurrentDirectory()
     {
 #if FEATURE_LEGACY_GETCURRENTDIRECTORY
         if (IsWindows)
         {
-            int bufferSize = GetCurrentDirectoryWin32(0, null);
-            char* buffer = stackalloc char[bufferSize];
-            int pathLength = GetCurrentDirectoryWin32(bufferSize, buffer);
-            return new string(buffer, startIndex: 0, length: pathLength);
+            unsafe
+            {
+                int bufferSize = GetCurrentDirectoryWin32(0, null);
+                char* buffer = stackalloc char[bufferSize];
+                int pathLength = GetCurrentDirectoryWin32(bufferSize, buffer);
+                return new string(buffer, startIndex: 0, length: pathLength);
+            }
         }
 #endif
         return Directory.GetCurrentDirectory();
diff --git a/src/MSBuild.Bootstrap.Utils/Tasks/InstallDotNetCoreTask.cs b/src/MSBuild.Bootstrap.Utils/Tasks/InstallDotNetCoreTask.cs
index 9606b11002d..15d35446d8a 100644
--- a/src/MSBuild.Bootstrap.Utils/Tasks/InstallDotNetCoreTask.cs
+++ b/src/MSBuild.Bootstrap.Utils/Tasks/InstallDotNetCoreTask.cs
@@ -154,13 +154,32 @@ private ScriptExecutionSettings SetupScriptsExecutionSettings()
         {
             string scriptExtension = IsWindows ? "ps1" : "sh";
             string scriptPath = Path.Combine(DotNetInstallScriptRootPath, $"{ScriptName}.{scriptExtension}");
+            // On Windows the native command-line parser treats a backslash before the closing quote as
+            // escaping it (e.g. "C:\dir\" becomes C:\dir"), so trim a trailing separator before quoting.
+            string installDir = TrimTrailingDirectorySeparators(InstallDir);
             string scriptArgs = IsWindows
-                ? $"-NoProfile -ExecutionPolicy Bypass -File {scriptPath} -Version {Version} -InstallDir {InstallDir}"
-                : $"{scriptPath} --version {Version} --install-dir {InstallDir}";
+                ? $"-NoProfile -ExecutionPolicy Bypass -File \"{scriptPath}\" -Version {Version} -InstallDir \"{installDir}\""
+                : $"\"{scriptPath}\" --version {Version} --install-dir \"{installDir}\"";
 
             return new ScriptExecutionSettings($"{ScriptName}.{scriptExtension}", scriptPath, scriptArgs);
         }
 
+        /// <summary>
+        /// Trims trailing directory separators while preserving a path root (e.g. "C:\").
+        /// </summary>
+        private static string TrimTrailingDirectorySeparators(string path)
+        {
+            string root = Path.GetPathRoot(path) ?? string.Empty;
+            while (path.Length > root.Length &&
+                   (path[path.Length - 1] == Path.DirectorySeparatorChar ||
+                    path[path.Length - 1] == Path.AltDirectorySeparatorChar))
+            {
+                path = path.Substring(0, path.Length - 1);
+            }
+
+            return path;
+        }
+
         /// <summary>
         /// A private struct to hold settings for script execution.
         /// </summary>