diff --git a/apps/desktop/src/services/BuiltInToolService/tools/bash/helper.ts b/apps/desktop/src/services/BuiltInToolService/tools/bash/helper.ts
index 81cf4e6d..2eb8cb77 100644
--- a/apps/desktop/src/services/BuiltInToolService/tools/bash/helper.ts
+++ b/apps/desktop/src/services/BuiltInToolService/tools/bash/helper.ts
@@ -16,7 +16,49 @@ import {
 } from './constants';
 
 function normalizeDirectoryPath(path: string): string {
-    return path.replace(/\//g, '\\').replace(/\\+$/, '').toLowerCase();
+    const normalizedSeparators = path.trim().replace(/\//g, '\\').replace(/\\+$/, '');
+    const uncMatch = /^\\\\([^\\]+)\\([^\\]+)(?:\\(.*))?$/.exec(normalizedSeparators);
+    const driveMatch = /^([a-zA-Z]:)(?:\\(.*))?$/.exec(normalizedSeparators);
+    const hasRoot = normalizedSeparators.startsWith('\\');
+    const prefix =
+        uncMatch && uncMatch[1] && uncMatch[2]
+            ? `\\\\${uncMatch[1].toLowerCase()}\\${uncMatch[2].toLowerCase()}`
+            : (driveMatch?.[1]?.toLowerCase() ?? (hasRoot ? '\\' : ''));
+    const body = uncMatch
+        ? (uncMatch[3] ?? '')
+        : driveMatch
+          ? (driveMatch[2] ?? '')
+          : normalizedSeparators.replace(/^\\+/, '');
+    const resolvedSegments: string[] = [];
+
+    for (const segment of body.split(/\\+/)) {
+        if (!segment || segment === '.') {
+            continue;
+        }
+
+        if (segment === '..') {
+            const lastSegment = resolvedSegments[resolvedSegments.length - 1];
+            if (lastSegment && lastSegment !== '..') {
+                resolvedSegments.pop();
+            } else if (!prefix) {
+                resolvedSegments.push(segment);
+            }
+            continue;
+        }
+
+        resolvedSegments.push(segment.toLowerCase());
+    }
+
+    const normalizedBody = resolvedSegments.join('\\');
+    if (!prefix) {
+        return normalizedBody;
+    }
+
+    if (!normalizedBody) {
+        return prefix;
+    }
+
+    return prefix.endsWith('\\') ? `${prefix}${normalizedBody}` : `${prefix}\\${normalizedBody}`;
 }
 
 function isWithinAllowedDirectory(path: string, allowlist: string[]): boolean {
diff --git a/apps/desktop/tests/services/BuiltInToolService/tools/bash/helper.test.ts b/apps/desktop/tests/services/BuiltInToolService/tools/bash/helper.test.ts
index 15741d99..f9b5c29c 100644
--- a/apps/desktop/tests/services/BuiltInToolService/tools/bash/helper.test.ts
+++ b/apps/desktop/tests/services/BuiltInToolService/tools/bash/helper.test.ts
@@ -94,6 +94,48 @@ describe('resolveCommandContext', () => {
         ).rejects.toThrow('Working directory is outside the allowed scope');
     });
 
+    it('rejects working directories that escape the allowlist with parent segments', async () => {
+        setLocale('en-US');
+        const config = {
+            ...baseConfig,
+            allowedWorkingDirectories: ['D:/allowed'],
+        };
+
+        await expect(
+            resolveCommandContext(
+                { command: 'dir', workingDirectory: 'D:/allowed/../other' },
+                config
+            )
+        ).rejects.toThrow('Working directory is outside the allowed scope');
+    });
+
+    it('rejects relative working directories that escape with consecutive parent segments', async () => {
+        setLocale('en-US');
+        const config = {
+            ...baseConfig,
+            allowedWorkingDirectories: ['foo'],
+        };
+
+        await expect(
+            resolveCommandContext({ command: 'dir', workingDirectory: '../../foo' }, config)
+        ).rejects.toThrow('Working directory is outside the allowed scope');
+    });
+
+    it('rejects UNC paths that escape to a sibling share before re-entering the allowlist', async () => {
+        setLocale('en-US');
+        const config = {
+            ...baseConfig,
+            allowedWorkingDirectories: ['\\\\server\\share'],
+        };
+
+        await expect(
+            resolveCommandContext(
+                { command: 'dir', workingDirectory: '\\\\server\\other\\..\\share\\secret' },
+                config
+            )
+        ).rejects.toThrow('Working directory is outside the allowed scope');
+    });
+
     it('accepts command inside allowed directories', async () => {
         const config = {
             ...baseConfig,