diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 897275001d..a20dc402ba 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -1102,6 +1102,18 @@ jobs:
         with:
           tool: cargo-nextest
 
+      # Keep fixtures outside runner.temp: setup-node writes an .npmrc there,
+      # which Yarn Classic discovers when walking parent directories.
+      - name: Create NTFS temp directory for case-sensitive shim snapshots
+        if: matrix.shard == 1
+        id: snapshot-temp
+        shell: pwsh
+        run: |
+          $volume = [System.IO.Path]::GetPathRoot($env:RUNNER_TEMP)
+          $snapshotTemp = Join-Path $volume ('vp-snapshots-' + [guid]::NewGuid().ToString('N'))
+          New-Item -ItemType Directory -Path $snapshotTemp | Out-Null
+          "directory=$snapshotTemp" >> $env:GITHUB_OUTPUT
+
       # `cargo-nextest` is invoked directly so the job never depends on the
       # runner's Rust toolchain. --workspace-remap makes nextest rewrite
       # CARGO_MANIFEST_DIR and CARGO_BIN_EXE_vpt to this checkout, which is
@@ -1121,7 +1133,20 @@ jobs:
           export VP_SNAP_PWSH_BIN="$(cygpath -w "$(command -v pwsh.exe)")"
           # --no-fail-fast: on a snapshot suite every diff is diagnostic
           # signal; cancelling on the first failure hides the rest.
-          cargo-nextest nextest run --archive-file windows-snapshot-tests.tar.zst --workspace-remap . --no-fail-fast --partition hash:${{ matrix.shard }}/3
+          test_exit=0
+          # This fixture requires case-sensitive directory support, which the
+          # default temp directory on these runners does not provide.
+          cargo-nextest nextest run --archive-file windows-snapshot-tests.tar.zst --workspace-remap . --no-fail-fast --partition hash:${{ matrix.shard }}/3 \
+            -E 'not test(windows_case_sensitive_shims)' || test_exit=$?
+
+          if [[ '${{ matrix.shard }}' == '1' ]]; then
+            # Run both flavors on NTFS once. Rust's GetTempPath2 ignores
+            # TEMP/TMP under the SYSTEM account, so override SystemTemp.
+            SystemTemp='${{ steps.snapshot-temp.outputs.directory }}' \
+              cargo-nextest nextest run --archive-file windows-snapshot-tests.tar.zst --workspace-remap . --no-fail-fast \
+                -E 'test(windows_case_sensitive_shims)' || test_exit=$?
+          fi
+          exit "$test_exit"
         env:
           RUST_BACKTRACE: '1'
           # Keep Windows env parity with the `test` recipe in justfile.
diff --git a/Cargo.lock b/Cargo.lock
index e7e53025df..b7155d0f89 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -8923,6 +8923,7 @@ name = "vp_shared"
 version = "0.0.0"
 dependencies = [
  "console",
+ "cow-utils",
  "directories",
  "nix 0.30.1",
  "reqwest",
diff --git a/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/later-shim.cjs b/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/later-shim.cjs
new file mode 100644
index 0000000000..c1c6e6807f
--- /dev/null
+++ b/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/later-shim.cjs
@@ -0,0 +1,4 @@
+const fs = require('node:fs');
+
+fs.mkdirSync('node_modules/.bin', { recursive: true });
+fs.writeFileSync('node_modules/.bin/astro.CMD', '@echo wrong workspace shim %*\r\n');
diff --git a/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/local-cli.cjs b/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/local-cli.cjs
new file mode 100644
index 0000000000..6a616b505b
--- /dev/null
+++ b/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/local-cli.cjs
@@ -0,0 +1,13 @@
+const { execFileSync } = require('node:child_process');
+const path = require('node:path');
+
+const vp = path.join(path.dirname(require.resolve('vite-plus/package.json')), 'bin', 'vp');
+// The runner's node shim can expand PATHEXT before this script starts.
+// Reset it in a new process that launches real Node directly, so only the
+// NAPI initializer can supply the lowercase extension for this CLI lookup.
+execFileSync(process.execPath, [vp, 'exec', 'astro', '--version'], {
+  cwd: path.resolve('packages/app'),
+  env: { ...process.env, PATHEXT: '.COM;.EXE;.BAT;.CMD' },
+  stdio: 'inherit',
+  timeout: 30000,
+});
diff --git a/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/package.json b/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/package.json
new file mode 100644
index 0000000000..349202b9ec
--- /dev/null
+++ b/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/package.json
@@ -0,0 +1,8 @@
+{
+  "name": "case-sensitive-shims",
+  "private": true,
+  "packageManager": "pnpm@12.4.1",
+  "scripts": {
+    "probe": "vp run --filter @fixture/app probe"
+  }
+}
diff --git a/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/packages/app/package.json b/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/packages/app/package.json
new file mode 100644
index 0000000000..5b3bcd0b65
--- /dev/null
+++ b/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/packages/app/package.json
@@ -0,0 +1,8 @@
+{
+  "name": "@fixture/app",
+  "private": true,
+  "scripts": {
+    "probe": "astro --version",
+    "priority": "node-priority -e \"process.exit(0)\""
+  }
+}
diff --git a/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/packages/app/print.cjs b/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/packages/app/print.cjs
new file mode 100644
index 0000000000..2397d28d99
--- /dev/null
+++ b/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/packages/app/print.cjs
@@ -0,0 +1 @@
+console.log('local shim', ...process.argv.slice(2));
diff --git a/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/packages/app/vite.config.ts b/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/packages/app/vite.config.ts
new file mode 100644
index 0000000000..d6d4b1aeea
--- /dev/null
+++ b/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/packages/app/vite.config.ts
@@ -0,0 +1,9 @@
+export default {
+  run: {
+    tasks: {
+      cached: {
+        command: "astro cached",
+      },
+    },
+  },
+};
diff --git a/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/pnpm-workspace.yaml b/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/pnpm-workspace.yaml
new file mode 100644
index 0000000000..924b55f42e
--- /dev/null
+++ b/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/pnpm-workspace.yaml
@@ -0,0 +1,2 @@
+packages:
+  - packages/*
diff --git a/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/setup.cjs b/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/setup.cjs
new file mode 100644
index 0000000000..f9f8a36665
--- /dev/null
+++ b/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/setup.cjs
@@ -0,0 +1,16 @@
+const assert = require('node:assert/strict');
+const { execFileSync } = require('node:child_process');
+const fs = require('node:fs');
+const path = require('node:path');
+
+const bin = path.resolve('packages/app/node_modules/.bin');
+fs.mkdirSync(bin, { recursive: true });
+// The directory must be empty when case sensitivity is enabled. Do not depend
+// on the checkout's NTFS flags or the casing chosen by a package manager.
+execFileSync('fsutil.exe', ['file', 'setCaseSensitiveInfo', bin, 'enable'], { stdio: 'inherit' });
+fs.writeFileSync(path.join(bin, 'astro.cmd'), '@echo off\r\nnode "%~dp0/../../print.cjs" %*\r\n');
+// A lowercase executable must win over an uppercase command shim in the same directory.
+fs.copyFileSync(process.execPath, path.join(bin, 'node-priority.exe'));
+fs.writeFileSync(path.join(bin, 'node-priority.CMD'), '@echo wrong cmd shim\r\n@exit /b 1\r\n');
+assert.equal(fs.existsSync(path.join(bin, 'astro.CMD')), false);
+assert.ok(process.env.PATHEXT.split(';').includes('.CMD'));
diff --git a/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/snapshots.toml b/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/snapshots.toml
new file mode 100644
index 0000000000..5ff306114c
--- /dev/null
+++ b/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/snapshots.toml
@@ -0,0 +1,27 @@
+[[case]]
+name = "windows_case_sensitive_shims"
+vp = ["local", "global"]
+skip-platforms = ["linux", "macos"]
+env = { PATHEXT = ".COM;.EXE;.BAT;.CMD" }
+steps = [
+  { argv = ["node", "setup.cjs"], snapshot = false },
+  { argv = ["vp", "run", "priority"], cwd = "packages/app", tty = false, snapshot = false },
+  { argv = ["vp", "exec", "node-priority", "-e", "process.exit(0)"], cwd = "packages/app", tty = false, snapshot = false },
+  { argv = ["vp", "run", "probe"], tty = false, comment = "Nested task planning resolves the lowercase shim with uppercase PATHEXT." },
+  { argv = ["vp", "exec", "astro", "--version"], cwd = "packages/app", tty = false },
+  { argv = ["node", "later-shim.cjs"], snapshot = false },
+  { argv = ["vp", "run", "probe"], tty = false, comment = "The earlier package-local lowercase shim wins over a later uppercase shim." },
+  { argv = ["vp", "exec", "astro", "--version"], cwd = "packages/app", tty = false },
+  { argv = ["vp", "run", "cached"], cwd = "packages/app", tty = false },
+  { argv = ["vp", "run", "cached"], cwd = "packages/app", tty = false, comment = "Resolving the program keeps the task's cache behavior." },
+]
+
+[[case]]
+name = "windows_case_sensitive_shims_external_node"
+vp = "local"
+skip-platforms = ["linux", "macos"]
+env = { PATHEXT = ".COM;.EXE;.BAT;.CMD" }
+steps = [
+  { argv = ["node", "setup.cjs"], snapshot = false },
+  { argv = ["node", "local-cli.cjs"], tty = false, comment = "The local CLI resolves the lowercase shim when real Node starts with uppercase PATHEXT." },
+]
diff --git a/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/snapshots/windows_case_sensitive_shims.global.md b/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/snapshots/windows_case_sensitive_shims.global.md
new file mode 100644
index 0000000000..6a63dd9f6a
--- /dev/null
+++ b/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/snapshots/windows_case_sensitive_shims.global.md
@@ -0,0 +1,62 @@
+# windows_case_sensitive_shims
+
+## `node setup.cjs`
+
+
+## `cd packages/app && vp run priority`
+
+
+## `cd packages/app && vp exec node-priority -e process.exit(0)`
+
+
+## `vp run probe`
+
+Nested task planning resolves the lowercase shim with uppercase PATHEXT.
+
+```
+~/packages/app$ astro --version ⊘ cache disabled
+local shim --version
+```
+
+## `cd packages/app && vp exec astro --version`
+
+```
+local shim --version
+```
+
+## `node later-shim.cjs`
+
+
+## `vp run probe`
+
+The earlier package-local lowercase shim wins over a later uppercase shim.
+
+```
+~/packages/app$ astro --version ⊘ cache disabled
+local shim --version
+```
+
+## `cd packages/app && vp exec astro --version`
+
+```
+local shim --version
+```
+
+## `cd packages/app && vp run cached`
+
+```
+~/packages/app$ astro cached
+local shim cached
+```
+
+## `cd packages/app && vp run cached`
+
+Resolving the program keeps the task's cache behavior.
+
+```
+~/packages/app$ astro cached ◉ cache hit, replaying
+local shim cached
+
+---
+vp run: cache hit, <duration> saved.
+```
diff --git a/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/snapshots/windows_case_sensitive_shims.local.md b/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/snapshots/windows_case_sensitive_shims.local.md
new file mode 100644
index 0000000000..6a63dd9f6a
--- /dev/null
+++ b/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/snapshots/windows_case_sensitive_shims.local.md
@@ -0,0 +1,62 @@
+# windows_case_sensitive_shims
+
+## `node setup.cjs`
+
+
+## `cd packages/app && vp run priority`
+
+
+## `cd packages/app && vp exec node-priority -e process.exit(0)`
+
+
+## `vp run probe`
+
+Nested task planning resolves the lowercase shim with uppercase PATHEXT.
+
+```
+~/packages/app$ astro --version ⊘ cache disabled
+local shim --version
+```
+
+## `cd packages/app && vp exec astro --version`
+
+```
+local shim --version
+```
+
+## `node later-shim.cjs`
+
+
+## `vp run probe`
+
+The earlier package-local lowercase shim wins over a later uppercase shim.
+
+```
+~/packages/app$ astro --version ⊘ cache disabled
+local shim --version
+```
+
+## `cd packages/app && vp exec astro --version`
+
+```
+local shim --version
+```
+
+## `cd packages/app && vp run cached`
+
+```
+~/packages/app$ astro cached
+local shim cached
+```
+
+## `cd packages/app && vp run cached`
+
+Resolving the program keeps the task's cache behavior.
+
+```
+~/packages/app$ astro cached ◉ cache hit, replaying
+local shim cached
+
+---
+vp run: cache hit, <duration> saved.
+```
diff --git a/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/snapshots/windows_case_sensitive_shims_external_node.md b/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/snapshots/windows_case_sensitive_shims_external_node.md
new file mode 100644
index 0000000000..1699845cd4
--- /dev/null
+++ b/crates/vp_cli_snapshots/tests/cli_snapshots/fixtures/windows_case_sensitive_shims/snapshots/windows_case_sensitive_shims_external_node.md
@@ -0,0 +1,12 @@
+# windows_case_sensitive_shims_external_node
+
+## `node setup.cjs`
+
+
+## `node local-cli.cjs`
+
+The local CLI resolves the lowercase shim when real Node starts with uppercase PATHEXT.
+
+```
+local shim --version
+```
diff --git a/crates/vp_global_cli/src/main.rs b/crates/vp_global_cli/src/main.rs
index 292791805b..4bcae58dea 100644
--- a/crates/vp_global_cli/src/main.rs
+++ b/crates/vp_global_cli/src/main.rs
@@ -381,6 +381,7 @@ async fn main() -> ExitCode {
     }
 
     vp_shared::ensure_blocking_stdio();
+    vp_shared::ensure_windows_pathext();
 
     // Initialize tracing
     vp_shared::init_tracing();
diff --git a/crates/vp_shared/Cargo.toml b/crates/vp_shared/Cargo.toml
index ecc58afb7d..62d4158f57 100644
--- a/crates/vp_shared/Cargo.toml
+++ b/crates/vp_shared/Cargo.toml
@@ -18,6 +18,7 @@ test-utils = ["dep:temp-env", "dep:tempfile"]
 directories = { workspace = true }
 nix = { workspace = true, features = ["fs", "poll", "term"] }
 console = { workspace = true }
+cow-utils = { workspace = true }
 serde = { workspace = true }
 # use `preserve_order` feature to preserve the order of the fields in `package.json`
 serde_json = { workspace = true, features = ["preserve_order"] }
diff --git a/crates/vp_shared/src/lib.rs b/crates/vp_shared/src/lib.rs
index ead1abf014..1ec2a26c13 100644
--- a/crates/vp_shared/src/lib.rs
+++ b/crates/vp_shared/src/lib.rs
@@ -39,7 +39,9 @@ pub use json_edit::{JsonStyle, edit_json_object, insert_after};
 pub use package_json::{
     DevEngineDependency, DevEngineField, DevEngines, Engines, OnFail, PackageJson, dev_engine_entry,
 };
-pub use path_env::{PrependOptions, ToolPathEnv, prepend_tools_to_path_env};
+pub use path_env::{
+    PrependOptions, ToolPathEnv, ensure_windows_pathext, prepend_tools_to_path_env,
+};
 pub use process::exit_code_from_status;
 pub use stdio::ensure_blocking_stdio;
 pub use tls::ensure_tls_provider;
diff --git a/crates/vp_shared/src/path_env.rs b/crates/vp_shared/src/path_env.rs
index 33ddba5cf8..b8c03c0580 100644
--- a/crates/vp_shared/src/path_env.rs
+++ b/crates/vp_shared/src/path_env.rs
@@ -1,4 +1,4 @@
-//! PATH environment variable manipulation utilities.
+//! PATH and PATHEXT environment variable manipulation utilities.
 //!
 //! This module provides functions for prepending directories to the PATH
 //! environment variable with various deduplication strategies.
@@ -9,6 +9,44 @@ use vt_path::AbsolutePath;
 
 use crate::env_vars;
 
+/// Add uppercase and lowercase variants of each configured Windows extension.
+/// Call during CLI initialization, before `which` caches PATHEXT. This also
+/// supplies the same extension order to Vite Task, fspy, and child processes.
+pub fn ensure_windows_pathext() {
+    #[cfg(windows)]
+    if let Ok(pathext) = env::var("PATHEXT") {
+        let expanded = expand_pathext_case_variants(&pathext);
+        if expanded != pathext {
+            // SAFETY: Environment mutation is thread-safe on Windows. This is
+            // also called when the NAPI binding loads in a Node.js process.
+            unsafe { env::set_var("PATHEXT", expanded) };
+        }
+    }
+}
+
+#[cfg(any(windows, test))]
+fn expand_pathext_case_variants(pathext: &str) -> String {
+    use std::borrow::Cow;
+
+    use cow_utils::CowUtils;
+
+    let mut extensions = Vec::new();
+    for extension in pathext.split(';') {
+        // Keep each variant next to its original extension so .EXE and .exe
+        // both precede .CMD and .cmd in the standard Windows search order.
+        for variant in [
+            Cow::Borrowed(extension),
+            extension.cow_to_ascii_uppercase(),
+            extension.cow_to_ascii_lowercase(),
+        ] {
+            if !extensions.contains(&variant) {
+                extensions.push(variant);
+            }
+        }
+    }
+    extensions.join(";")
+}
+
 /// PATH and the tools whose real binary directories Vite+ has injected into it.
 /// Keep both values together when preparing a child process environment.
 #[derive(Debug, Clone)]
@@ -99,6 +137,22 @@ mod tests {
 
     use super::*;
 
+    #[test]
+    fn pathext_keeps_exe_variants_before_cmd_variants() {
+        assert_eq!(
+            expand_pathext_case_variants(".COM;.EXE;.BAT;.CMD"),
+            ".COM;.com;.EXE;.exe;.BAT;.bat;.CMD;.cmd"
+        );
+    }
+
+    #[test]
+    fn pathext_preserves_custom_order_and_is_idempotent() {
+        let expanded = expand_pathext_case_variants(".cmd;.exe;.CMD;.PY");
+        assert_eq!(expanded, ".cmd;.CMD;.exe;.EXE;.PY;.py");
+        assert_eq!(expand_pathext_case_variants(&expanded), expanded);
+        assert_eq!(expand_pathext_case_variants(""), "");
+    }
+
     #[test]
     fn injected_tools_accumulate_without_changing_other_environments() {
         let original = ToolPathEnv::new(OsString::new(), "node,npm,npx,node");
diff --git a/packages/cli/binding/src/lib.rs b/packages/cli/binding/src/lib.rs
index e195bfb55b..cb5b1368bb 100644
--- a/packages/cli/binding/src/lib.rs
+++ b/packages/cli/binding/src/lib.rs
@@ -45,6 +45,7 @@ use crate::cli::{
 #[allow(clippy::disallowed_macros)]
 pub fn init() {
     vp_shared::ensure_blocking_stdio();
+    vp_shared::ensure_windows_pathext();
     crate::cli::init_tracing();
 
     // Install a Vite+ panic hook so panics are correctly attributed to Vite+.