🛡️ Sentinel: [HIGH] Fix XSS risk in folder names by google-labs-jules[bot] · Pull Request #134 · abhimehro/ctrld-sync

google-labs-jules · 2026-01-26T11:18:21Z

🛡️ Sentinel: [HIGH] Fix XSS risk in folder names

Vulnerability:
The application parses folder names from external JSON files (group.group) but failed to validate them against XSS payloads. While rules were validated, folder names were not, allowing a malicious list provider to inject Stored XSS via crafted folder names (e.g., <script>alert(1)</script>).

Fix:

Added is_valid_folder_name function to block dangerous characters (<, >, ", ', backtick) and ensure printability.
Updated validate_folder_data to enforce string type and apply is_valid_folder_name check on the folder name.
Added comprehensive tests in tests/test_folder_validation.py.

Verification:
Run pytest tests/test_folder_validation.py to verify that XSS payloads are now rejected (return False).
Run pytest to ensure no regressions.

PR created automatically by Jules for task 2430422589834267156 started by @abhimehro

Add strict validation for folder names parsed from external JSON files to prevent potential Stored XSS vulnerabilities. - Implement `is_valid_folder_name` to block XSS characters (< > " ' `) - Update `validate_folder_data` to check folder names - Add tests in `tests/test_folder_validation.py` covering XSS payloads and invalid types - Add journal entry for incomplete input validation scope

google-labs-jules · 2026-01-26T11:18:22Z

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trunk-io · 2026-01-26T11:18:25Z

Merging to main in this repository is managed by Trunk.

To merge this pull request, check the box to the left or comment /trunk merge below.

tests/test_folder_validation.py

+    try:
+        # Case 1: Valid Folder Name
+        valid_data = {"group": {"group": "Safe Folder Name (Work)"}}
+        assert main.validate_folder_data(valid_data, "http://valid.com") is True


tests/test_folder_validation.py

+
+        # Case 2: XSS Payload
+        xss_data = {"group": {"group": "<script>alert(1)</script>"}}
+        assert main.validate_folder_data(xss_data, "http://evil.com") is False


tests/test_folder_validation.py

+
+        # Case 3: Invalid Type
+        invalid_type_data = {"group": {"group": 123}}
+        assert main.validate_folder_data(invalid_type_data, "http://badtype.com") is False


tests/test_folder_validation.py

+
+        # Case 4: Dangerous characters
+        dangerous_data = {"group": {"group": "Folder\"Name"}}
+        assert main.validate_folder_data(dangerous_data, "http://dangerous.com") is False


.jules/sentinel.md

 1. Implement strict validation on all data items from external lists (`is_valid_rule`).
 2. Filter out items containing dangerous characters (`<`, `>`, `"` etc.) or control codes.
+
+## 2026-06-01 - [Incomplete Input Validation Scope]


.jules/sentinel.md

 1. Implement strict validation on all data items from external lists (`is_valid_rule`).
 2. Filter out items containing dangerous characters (`<`, `>`, `"` etc.) or control codes.
+
+## 2026-06-01 - [Incomplete Input Validation Scope]


tests/test_folder_validation.py

+    try:
+        # Case 1: Valid Folder Name
+        valid_data = {"group": {"group": "Safe Folder Name (Work)"}}
+        assert main.validate_folder_data(valid_data, "http://valid.com") is True


tests/test_folder_validation.py

+
+        # Case 2: XSS Payload
+        xss_data = {"group": {"group": "<script>alert(1)</script>"}}
+        assert main.validate_folder_data(xss_data, "http://evil.com") is False


tests/test_folder_validation.py

+
+        # Case 3: Invalid Type
+        invalid_type_data = {"group": {"group": 123}}
+        assert main.validate_folder_data(invalid_type_data, "http://badtype.com") is False


tests/test_folder_validation.py

+
+        # Case 4: Dangerous characters
+        dangerous_data = {"group": {"group": "Folder\"Name"}}
+        assert main.validate_folder_data(dangerous_data, "http://dangerous.com") is False


main.py

+    # Security: Validate folder name
+    folder_name = data["group"]["group"]
+    if not isinstance(folder_name, str):
+        log.error(f"Invalid data from {sanitize_for_log(url)}: Folder name must be a string.")


main.py

+        return False
+
+    if not is_valid_folder_name(folder_name):
+        log.error(f"Invalid data from {sanitize_for_log(url)}: Unsafe folder name detected.")


tests/test_folder_validation.py

@@ -0,0 +1,32 @@
+import pytest


tests/test_folder_validation.py

@@ -0,0 +1,32 @@
+import pytest


tests/test_folder_validation.py

@@ -0,0 +1,32 @@
+import pytest


tests/test_folder_validation.py

@@ -0,0 +1,32 @@
+import pytest
+from unittest.mock import MagicMock


tests/test_folder_validation.py

@@ -0,0 +1,32 @@
+import pytest


tests/test_folder_validation.py

@@ -0,0 +1,32 @@
+import pytest


tests/test_folder_validation.py

@@ -0,0 +1,32 @@
+import pytest
+from unittest.mock import MagicMock


main.py

+    # Security: Validate folder name
+    folder_name = data["group"]["group"]
+    if not isinstance(folder_name, str):
+        log.error(f"Invalid data from {sanitize_for_log(url)}: Folder name must be a string.")


main.py

+        return False
+
+    if not is_valid_folder_name(folder_name):
+        log.error(f"Invalid data from {sanitize_for_log(url)}: Unsafe folder name detected.")


tests/test_folder_validation.py

@@ -0,0 +1,32 @@
+import pytest


Copilot

Pull request overview

This PR fixes a stored XSS vulnerability in folder names by adding validation to prevent malicious characters from being injected through external JSON sources. The vulnerability existed because while rule content was validated, folder names (metadata) were not, allowing XSS payloads to be stored and potentially executed in the UI.

Changes:

Added is_valid_folder_name function to validate folder names against XSS-dangerous characters
Updated validate_folder_data to enforce string type checking and apply folder name validation
Added security tests to verify XSS payloads are rejected

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 4 comments.

File	Description
main.py	Added `is_valid_folder_name` validation function and integrated it into `validate_folder_data` to reject dangerous characters in folder names
tests/test_folder_validation.py	Added comprehensive test cases for folder name security validation including XSS payloads, type validation, and dangerous characters
.jules/sentinel.md	Documented the vulnerability, learning, and prevention measures for incomplete input validation scope

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Copilot · 2026-01-27T07:38:12Z

main.py

+    if not name or not name.isprintable():
+        return False
+
+    # Block XSS and HTML injection characters
+    dangerous_chars = set("<>\"'`")
+    if any(c in dangerous_chars for c in name):


The validation in is_valid_folder_name checks the folder name before it's stripped, but the actual usage throughout the codebase (lines 721, 841, 872 in main.py) strips the folder name with .strip() before using it. This creates a validation bypass: a folder name consisting only of whitespace characters or one that becomes empty after stripping could pass validation but then cause issues or unexpected behavior when processed. The validation should either strip the name before checking, or explicitly reject names that would become empty after stripping. Consider modifying the function to: strip the name first, then check if it's empty.

Suggested change

if not name or not name.isprintable():

return False

# Block XSS and HTML injection characters

dangerous_chars = set("<>\"'`")

if any(c in dangerous_chars for c in name):

# Normalize the folder name the same way it is used elsewhere

stripped = name.strip()

# Reject names that are empty or only whitespace after stripping

if not stripped or not stripped.isprintable():

return False

# Block XSS and HTML injection characters

dangerous_chars = set("<>\"'`")

if any(c in dangerous_chars for c in stripped):

Copilot · 2026-01-27T07:38:13Z

tests/test_folder_validation.py

+def test_folder_name_security():
+    """
+    Verify that validate_folder_data enforces security checks on folder names.
+    """
+    # Mock logger to verify errors
+    mock_log = MagicMock()
+    original_log = main.log
+    main.log = mock_log
+
+    try:
+        # Case 1: Valid Folder Name
+        valid_data = {"group": {"group": "Safe Folder Name (Work)"}}
+        assert main.validate_folder_data(valid_data, "http://valid.com") is True
+
+        # Case 2: XSS Payload
+        xss_data = {"group": {"group": "<script>alert(1)</script>"}}
+        assert main.validate_folder_data(xss_data, "http://evil.com") is False
+
+        # Case 3: Invalid Type
+        invalid_type_data = {"group": {"group": 123}}
+        assert main.validate_folder_data(invalid_type_data, "http://badtype.com") is False
+
+        # Case 4: Dangerous characters
+        dangerous_data = {"group": {"group": "Folder\"Name"}}
+        assert main.validate_folder_data(dangerous_data, "http://dangerous.com") is False
+
+    finally:
+        main.log = original_log


The test cases should include edge cases for whitespace handling since the actual code usage strips folder names with .strip(). Consider adding test cases for: folder names with leading/trailing whitespace (e.g., " Valid Name "), folder names that are only whitespace (e.g., " "), and folder names that become empty after stripping. These edge cases are important to verify that the validation properly handles the stripping behavior seen in the main code.

Copilot · 2026-01-27T07:38:13Z

tests/test_folder_validation.py

+        # Case 2: XSS Payload
+        xss_data = {"group": {"group": "<script>alert(1)</script>"}}
+        assert main.validate_folder_data(xss_data, "http://evil.com") is False
+
+        # Case 3: Invalid Type
+        invalid_type_data = {"group": {"group": 123}}
+        assert main.validate_folder_data(invalid_type_data, "http://badtype.com") is False
+
+        # Case 4: Dangerous characters
+        dangerous_data = {"group": {"group": "Folder\"Name"}}
+        assert main.validate_folder_data(dangerous_data, "http://dangerous.com") is False


The test should verify additional XSS vectors and edge cases beyond the basic script tag. Consider adding tests for: HTML event handlers without script tags (e.g., "onload=alert(1)"), HTML entities (e.g., "<script>"), mixed case attempts (though these may not bypass the character check), and Unicode normalization attacks if applicable. Also consider testing the backtick character explicitly since it's in the dangerous_chars set but not tested.

Copilot · 2026-01-27T07:38:13Z

tests/test_folder_validation.py

@@ -0,0 +1,32 @@
+import pytest


Import of 'pytest' is not used.

Suggested change

import pytest

github-actions bot added the python label Jan 26, 2026

github-advanced-security bot found potential problems Jan 26, 2026

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abhimehro assigned Copilot and abhimehro Jan 27, 2026

abhimehro marked this pull request as ready for review January 27, 2026 07:30

Copilot AI review requested due to automatic review settings January 27, 2026 07:30

Copilot started reviewing on behalf of abhimehro January 27, 2026 07:30 View session

Copilot AI reviewed Jan 27, 2026

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abhimehro merged commit 892db0f into main Jan 27, 2026
24 checks passed

abhimehro deleted the sentinel-folder-name-validation-2430422589834267156 branch January 27, 2026 12:20

		@@ -0,0 +1,32 @@
		import pytest
		from unittest.mock import MagicMock

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