Critical

changedetection.io has a Server Side Template Injection using Jinja2 which allows Remote Command Execution

  • Disclosed: 15.10.2024
  • Updated: 11.10.2026 15:17

Summary

A Server Side Template Injection in changedetection.io caused by usage of unsafe functions of Jinja2 allows Remote Command Execution on the server host.

Details

changedetection.io version: 0.45.20

bash
docker images
REPOSITORY                            TAG       IMAGE ID       CREATED        SIZE
dgtlmoon/changedetection.io           latest    53529c2e69f1   44 hours ago   423MB

The vulnerability is caused by the usage of vulnerable functions of Jinja2 template engine.

python
from jinja2 import Environment, BaseLoader
...
    # Get the notification body from datastore
    jinja2_env = Environment(loader=BaseLoader)
    n_body = jinja2_env.from_string(n_object.get('notification_body', '')).render(**notification_parameters)
    n_title = jinja2_env.from_string(n_object.get('notification_title', '')).render(**notification_parameters)

PoC

  1. Create/Edit a URL watch item
  2. Under Notifications tab insert this payload:
python
{{ self.__init__.__globals__.__builtins__.__import__('os').popen('id').read() }}

Screenshot from 2024-04-19 15-46-04

  1. See Telegram (or other supported messaging app) notification

Screenshot from 2024-04-19 16-02-12

Impact

In the PoC I've used id as payload and Telegram to read the result.
Attackers can run any system command without any restriction and they don't need to read the result in the notification app (e.g. they could use a reverse shell). The impact is critical as the attacker can completely takeover the server host. This can be reduced if changedetection access is protected by login page with a password, but this isn't required by the application (not by default and not enforced).

References

Credits

Edoardo Ottavianelli

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Python (PyPI) changedetection-io < 0.45.21 0.45.21

References

CVSS score 10/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Weakness (CWE)
CWE-1336
Platform
Python (PyPI)
Package
changedetection-io
Disclosed
15.10.2024
Updated
11.10.2026 15:17

Sources and licenses

OSV / GitHub Advisory Database - PYSEC-2026-310 - PyPA Advisory Database; CC BY 4.0

OSV / GitHub Advisory Database - GHSA-4r7v-whpg-8rx3 - 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.

All (20) in the archive
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

  1. 2023: 1
  2. 2024: 6
  3. 2025: 2
  4. 2026: 11
Severity:
  1. High · 7.5 CVE-2026-41895 <= 0.54.9 no fix
  2. High · 8.6 CVE-2026-27696 < 0.54.1 0.54.1
  3. High CVE-2025-52558 < 0.50.4 0.50.4
  4. changedetection.io has a Server Side Template Injection using Jinja2 which allows Remote Command Execution this entry
    Critical · 10.0 CVE-2024-32651 < 0.45.21 0.45.21

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