diff --git a/packages/vite/src/node/__tests__/dev.spec.ts b/packages/vite/src/node/__tests__/dev.spec.ts
index e0809e1c8cc7e7..0f0411f7485c40 100644
--- a/packages/vite/src/node/__tests__/dev.spec.ts
+++ b/packages/vite/src/node/__tests__/dev.spec.ts
@@ -122,6 +122,35 @@ describe('the dev server', () => {
     expect(server.config.safeModulePaths).not.toContain(externalEntry)
   })
 
+  test('does not mark unresolved SSR imports as safe', async () => {
+    const root = path.join(import.meta.dirname, 'fixtures', 'input-option')
+    const entry = normalizePath(path.join(root, 'unresolved-entry.js'))
+    const unresolvedImport = '/safe-module-path-unresolved'
+
+    server = await createServer({
+      configFile: false,
+      root,
+      optimizeDeps: { noDiscovery: true },
+      server: { middlewareMode: true, ws: false },
+      plugins: [
+        {
+          name: 'unresolved-ssr-import',
+          resolveId(id) {
+            if (id === '/unresolved-entry.js') return entry
+          },
+          load(id) {
+            if (id === entry)
+              return `import ${JSON.stringify(unresolvedImport)}`
+          },
+        },
+      ],
+    })
+
+    await server.environments.ssr.transformRequest('/unresolved-entry.js')
+
+    expect(server.config.safeModulePaths).not.toContain(unresolvedImport)
+  })
+
   test('silently resolves index.html as the fallback for every environment', async () => {
     const root = path.join(import.meta.dirname, 'fixtures', 'input-option')
     const clientEntry = normalizePath(path.join(root, 'client-index.html'))
diff --git a/packages/vite/src/node/plugins/importAnalysis.ts b/packages/vite/src/node/plugins/importAnalysis.ts
index fb0c34236a0055..c6adff0f3a18a2 100644
--- a/packages/vite/src/node/plugins/importAnalysis.ts
+++ b/packages/vite/src/node/plugins/importAnalysis.ts
@@ -46,7 +46,6 @@ import {
 import type { TransformPluginContext } from '../server/pluginContainer'
 import {
   createDebugger,
-  fsPathFromUrl,
   generateCodeFrame,
   getFileStartIndex,
   getHash,
@@ -587,13 +586,11 @@ export function importAnalysisPlugin(config: ResolvedConfig): Plugin {
 
             // normalize
             let [url, resolvedId] = await normalizeUrl(specifier, start)
+            if (resolvedId) {
+              config.safeModulePaths.add(cleanUrl(resolvedId))
+            }
             resolvedId = resolvedId || url
 
-            // record as safe modules
-            // safeModulesPath should not include the base prefix.
-            // See https://github.com/vitejs/vite/issues/9438#issuecomment-1465270409
-            config.safeModulePaths.add(fsPathFromUrl(stripBase(url, base)))
-
             if (url !== specifier) {
               let rewriteDone = false
               // optimizer-emitted imports resolve to the sibling file they
diff --git a/playground/fs-serve/__tests__/fs-serve.spec.ts b/playground/fs-serve/__tests__/fs-serve.spec.ts
index 42d1996513d585..e0118d8e479873 100644
--- a/playground/fs-serve/__tests__/fs-serve.spec.ts
+++ b/playground/fs-serve/__tests__/fs-serve.spec.ts
@@ -1,9 +1,17 @@
 import net from 'node:net'
 import path from 'node:path'
 import { describe, expect, test } from 'vitest'
-import { isBundledDev, isServe, isWindows, viteTestUrl } from '~utils'
+import { isBundledDev, isServe, isWindows, page, viteTestUrl } from '~utils'
 import './commonTests'
 
+describe.runIf(isServe)('safe module paths', () => {
+  test('keeps root-relative module URLs separate from absolute filesystem paths', async () => {
+    await expect
+      .poll(() => page.textContent('.safe-module-path-status'))
+      .toBe(isBundledDev || isWindows ? '404' : '403')
+  })
+})
+
 describe.runIf(isServe)('invalid request', () => {
   const sendRawRequest = async (baseUrl: string, requestTarget: string) => {
     return new Promise<string>((resolve, reject) => {
diff --git a/playground/fs-serve/root/safeModulePathPlugin.ts b/playground/fs-serve/root/safeModulePathPlugin.ts
new file mode 100644
index 00000000000000..36b93faaf84e34
--- /dev/null
+++ b/playground/fs-serve/root/safeModulePathPlugin.ts
@@ -0,0 +1,24 @@
+import path from 'node:path'
+import type { Plugin } from 'vite'
+
+const playgroundRoot = path.dirname(import.meta.dirname).replace(/\\/g, '/')
+const targetRoot = playgroundRoot.replace(/^[A-Z]:/i, '')
+const target = path.posix.join(targetRoot, 'root/unsafe.txt')
+const decoyId = path.posix.join(import.meta.dirname.replace(/\\/g, '/'), target)
+
+export default function safeModulePathPlugin(): Plugin {
+  return {
+    name: 'safe-module-path',
+    enforce: 'pre',
+    resolveId(id) {
+      if (id === 'virtual:safe-module-path-confusion') {
+        return decoyId
+      }
+    },
+    load(id) {
+      if (id === decoyId) {
+        return 'export {}'
+      }
+    },
+  }
+}
diff --git a/playground/fs-serve/root/src/index.html b/playground/fs-serve/root/src/index.html
index f3af4bcbb46a05..b21801e08a897b 100644
--- a/playground/fs-serve/root/src/index.html
+++ b/playground/fs-serve/root/src/index.html
@@ -9,11 +9,17 @@ <h2>Normal Import</h2>
   <pre class="virtual-svg"></pre>
 </div>
 
+<div>
+  <h2>Safe Module Path Access Isolation</h2>
+  <pre class="safe-module-path-status"></pre>
+</div>
+
 <!-- REPLACE WITH MATRIX TEST RESULT -->
 
 <script type="module">
   import '../../entry'
   import json, { msg } from '../../safe.json'
+  import 'virtual:safe-module-path-confusion'
   import './code.js'
 
   // Check virtual svg module still works
@@ -23,6 +29,13 @@ <h2>Normal Import</h2>
   text('.named', msg)
   text('.virtual-svg', fooSvg)
 
+  if (import.meta.env.DEV) {
+    const base = typeof BASE !== 'undefined' ? BASE : '/'
+    const hostFileUrl = `${base}@fs${ROOT}/root/unsafe.txt`
+    const response = await fetch(hostFileUrl)
+    text('.safe-module-path-status', response.status)
+  }
+
   function text(sel, text) {
     document.querySelector(sel).textContent = text
   }
diff --git a/playground/fs-serve/root/vite.config-base.js b/playground/fs-serve/root/vite.config-base.js
index 2b441374fc8ae9..ace859b5474de1 100644
--- a/playground/fs-serve/root/vite.config-base.js
+++ b/playground/fs-serve/root/vite.config-base.js
@@ -1,6 +1,7 @@
 import path from 'node:path'
 import { defineConfig } from 'vite'
 import matrixTestResultPlugin from './matrixTestResultPlugin.ts'
+import safeModulePathPlugin from './safeModulePathPlugin.ts'
 import svgVirtualModulePlugin from './svgVirtualModulePlugin.ts'
 import { getWindows83ShortNameForDotEnv } from './windows83Filename.ts'
 
@@ -36,5 +37,9 @@ export default defineConfig({
     BASE: JSON.stringify(BASE),
     DOTENV83SHORTNAME: JSON.stringify(getWindows83ShortNameForDotEnv()),
   },
-  plugins: [svgVirtualModulePlugin(), matrixTestResultPlugin()],
+  plugins: [
+    svgVirtualModulePlugin(),
+    safeModulePathPlugin(),
+    matrixTestResultPlugin(),
+  ],
 })
diff --git a/playground/fs-serve/root/vite.config-deny.js b/playground/fs-serve/root/vite.config-deny.js
index e00ee9069fe92d..678acbeae7a095 100644
--- a/playground/fs-serve/root/vite.config-deny.js
+++ b/playground/fs-serve/root/vite.config-deny.js
@@ -1,5 +1,6 @@
 import path from 'node:path'
 import { defineConfig } from 'vite'
+import safeModulePathPlugin from './safeModulePathPlugin.ts'
 import svgVirtualModulePlugin from './svgVirtualModulePlugin.ts'
 
 export default defineConfig({
@@ -19,5 +20,5 @@ export default defineConfig({
   define: {
     ROOT: JSON.stringify(path.dirname(import.meta.dirname).replace(/\\/g, '/')),
   },
-  plugins: [svgVirtualModulePlugin()],
+  plugins: [svgVirtualModulePlugin(), safeModulePathPlugin()],
 })
diff --git a/playground/fs-serve/root/vite.config.js b/playground/fs-serve/root/vite.config.js
index a5f744a985aa83..306b22ea7629a9 100644
--- a/playground/fs-serve/root/vite.config.js
+++ b/playground/fs-serve/root/vite.config.js
@@ -1,6 +1,7 @@
 import path from 'node:path'
 import { defineConfig } from 'vite'
 import matrixTestResultPlugin from './matrixTestResultPlugin.ts'
+import safeModulePathPlugin from './safeModulePathPlugin.ts'
 import svgVirtualModulePlugin from './svgVirtualModulePlugin.ts'
 import { getWindows83ShortNameForDotEnv } from './windows83Filename.ts'
 
@@ -32,5 +33,9 @@ export default defineConfig({
     ROOT: JSON.stringify(path.dirname(import.meta.dirname).replace(/\\/g, '/')),
     DOTENV83SHORTNAME: JSON.stringify(getWindows83ShortNameForDotEnv()),
   },
-  plugins: [svgVirtualModulePlugin(), matrixTestResultPlugin()],
+  plugins: [
+    svgVirtualModulePlugin(),
+    safeModulePathPlugin(),
+    matrixTestResultPlugin(),
+  ],
 })