diff --git a/scripts/lib/lint-staged-common.js b/scripts/lib/lint-staged-common.js
index 0cd3c17c8..6f2d45d55 100644
--- a/scripts/lib/lint-staged-common.js
+++ b/scripts/lib/lint-staged-common.js
@@ -318,7 +318,7 @@ function sanitizeFilePath(filePath, baseDir, allowedExtensions, maxFileSizeMB =
 
     // On Windows, lint-staged may pass paths like C:/path/to/file
     // Convert these to proper Windows format first
-    if (IS_WINDOWS && /^[A-Za-z]:[\\\\/]/.test(filePath)) {
+    if (IS_WINDOWS && /^[A-Za-z]:[\\/]/.test(filePath)) {
         normalizedPath = filePath.replaceAll("/", path.sep)
     }
 
diff --git a/scripts/lint-any.js b/scripts/lint-any.js
index da7ec42f3..7fd54df22 100644
--- a/scripts/lint-any.js
+++ b/scripts/lint-any.js
@@ -304,24 +304,32 @@ function runOxfmtCheck(files, fix) {
  * @param {string[]} files - Array of file paths
  * @param {boolean} fix - Whether to pass --fix
  * @param {boolean} clearCache - Whether to pass --clear-cache
- * @returns {{ scriptArgs: string[], tempFile: string | null }}
+ * @returns {{ scriptArgs: string[], cleanup: (() => void) | null }}
  */
 function buildScriptArgs(files, fix, clearCache) {
     const scriptArgs = []
-    let tempFile = null
+    let cleanup = null
 
     const totalLength = files.reduce((sum, f) => sum + f.length + 1, 0)
     if (totalLength > MAX_ARG_LENGTH) {
-        const RADIX = 36
-        const SUFFIX_LENGTH = 8
-        tempFile = path.join(
-            os.tmpdir(),
-            `lint-files-${Date.now()}-${Math.random()
-                .toString(RADIX)
-                .slice(2, 2 + SUFFIX_LENGTH)}.txt`,
-        )
-        fs.writeFileSync(tempFile, files.join("\n"), "utf8")
-        scriptArgs.push(`--files-from=${tempFile}`)
+        // Use mkdtempSync (private mode-0700 dir with cryptographic suffix) so the
+        // inner file cannot be predicted/preempted by another local process.
+        const tempDir = fs.mkdtempSync(path.join(os.tmpdir(), "lint-files-"))
+        const tempFile = path.join(tempDir, "files.txt")
+        cleanup = () => {
+            try {
+                fs.rmSync(tempDir, { recursive: true, force: true })
+            } catch {
+                /* Best-effort cleanup */
+            }
+        }
+        try {
+            fs.writeFileSync(tempFile, files.join("\n"), "utf8")
+            scriptArgs.push(`--files-from=${tempFile}`)
+        } catch (error) {
+            cleanup()
+            throw error
+        }
     } else {
         scriptArgs.push(...files)
     }
@@ -333,7 +341,7 @@ function buildScriptArgs(files, fix, clearCache) {
         scriptArgs.push("--clear-cache")
     }
 
-    return { scriptArgs, tempFile }
+    return { scriptArgs, cleanup }
 }
 
 /**
@@ -352,7 +360,7 @@ function runLinter(script, files, description, fix, clearCache) {
     console.log(`\n🔍 ${description} (${files.length} files)`)
 
     const scriptPath = path.join(__dirname, script)
-    const { scriptArgs, tempFile } = buildScriptArgs(files, fix, clearCache)
+    const { scriptArgs, cleanup } = buildScriptArgs(files, fix, clearCache)
 
     const result = spawnSync("node", [scriptPath, ...scriptArgs], {
         stdio: "inherit",
@@ -360,13 +368,7 @@ function runLinter(script, files, description, fix, clearCache) {
         env,
     })
 
-    if (tempFile) {
-        try {
-            fs.unlinkSync(tempFile)
-        } catch {
-            /* Best-effort cleanup */
-        }
-    }
+    cleanup?.()
 
     if (result.error) {
         console.error(`❌ Failed to run ${script}:`, result.error.message)
@@ -392,7 +394,7 @@ function runLinterAsync(script, files, description, fix, clearCache) {
     console.log(`\n🔍 ${description} (${files.length} files)`)
 
     const scriptPath = path.join(__dirname, script)
-    const { scriptArgs, tempFile } = buildScriptArgs(files, fix, clearCache)
+    const { scriptArgs, cleanup } = buildScriptArgs(files, fix, clearCache)
 
     return new Promise((resolve) => {
         const child = spawn("node", [scriptPath, ...scriptArgs], {
@@ -402,13 +404,7 @@ function runLinterAsync(script, files, description, fix, clearCache) {
         })
 
         child.on("close", (code, signal) => {
-            if (tempFile) {
-                try {
-                    fs.unlinkSync(tempFile)
-                } catch {
-                    /* Best-effort cleanup */
-                }
-            }
+            cleanup?.()
             if (signal) {
                 console.error(`❌ ${script} terminated by signal ${signal}`)
                 resolve(1)
@@ -417,13 +413,7 @@ function runLinterAsync(script, files, description, fix, clearCache) {
             resolve(code ?? 1)
         })
         child.on("error", (err) => {
-            if (tempFile) {
-                try {
-                    fs.unlinkSync(tempFile)
-                } catch {
-                    /* Best-effort cleanup */
-                }
-            }
+            cleanup?.()
             console.error(`❌ Failed to run ${script}:`, err.message)
             resolve(1)
         })
diff --git a/web/Program.cs b/web/Program.cs
index 5fee3318b..c5136eec7 100644
--- a/web/Program.cs
+++ b/web/Program.cs
@@ -30,7 +30,7 @@
 
 // Load .env.local for local development only (multiple-instance support)
 // Avoid loading in production - guard by ASPNETCORE_ENVIRONMENT.
-var envPath = Path.Combine(Directory.GetCurrentDirectory(), "../.env.local");
+var envPath = Path.Join(Directory.GetCurrentDirectory(), "../.env.local");
 var aspNetEnv = Environment.GetEnvironmentVariable("ASPNETCORE_ENVIRONMENT");
 if (string.Equals(aspNetEnv, "Development", StringComparison.OrdinalIgnoreCase)
     && File.Exists(envPath))
@@ -476,7 +476,7 @@ void RegisterDbContext<TContext>(string connectionStringKey) where TContext : Db
     {
         DefaultFileNames = new List<string> { "index.html" },
         FileProvider = new PhysicalFileProvider(
-            Path.Combine(builder.Environment.ContentRootPath, "wwwroot/vue")),
+            Path.Join(builder.Environment.ContentRootPath, "wwwroot/vue")),
         RequestPath = "/vue",
         RedirectToAppendTrailingSlash = true
     });
@@ -487,7 +487,7 @@ void RegisterDbContext<TContext>(string connectionStringKey) where TContext : Db
     app.UseStaticFiles(new StaticFileOptions
     {
         FileProvider = new PhysicalFileProvider(
-            Path.Combine(builder.Environment.ContentRootPath, "wwwroot/vue")),
+            Path.Join(builder.Environment.ContentRootPath, "wwwroot/vue")),
         RequestPath = "/2/vue"
     });
 
diff --git a/web/ViteProxyHelpers.cs b/web/ViteProxyHelpers.cs
index fa939bead..c45d6562a 100644
--- a/web/ViteProxyHelpers.cs
+++ b/web/ViteProxyHelpers.cs
@@ -339,7 +339,7 @@ public static async Task HandleProxyError(HttpContext context, Exception ex, ILo
                     }
                 }
 
-                var physicalPath = Path.Combine(context.RequestServices.GetRequiredService<IWebHostEnvironment>().WebRootPath,
+                var physicalPath = Path.Join(context.RequestServices.GetRequiredService<IWebHostEnvironment>().WebRootPath,
                     staticPath.TrimStart('/').Replace('/', Path.DirectorySeparatorChar));
 
                 // Prevent directory traversal: ensure the resolved physical path is within WebRootPath