CVE-2026-27645: changedetection.io Vulnerable to Reflected XSS in RSS Single Watch Error Response

CVE-2026-27645 · Severity: low · CVSS 3.1 · Published 2026-02-25

changedetection.io is a free open source web page change detection tool. In versions prior to 0.54.1, the RSS single-watch endpoint reflects the UUID path parameter directly in the HTTP response body without HTML escaping. Since Flask returns text/html by default for plain string responses, the browser parses and executes injected JavaScript. Version 0.54.1 contains a fix for the issue.

Technologies: changedetection.io (PyPI). Vendors: PyPI.

Quick answers

Is CVE-2026-27645 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-27645 being exploited in the wild.
How severe is CVE-2026-27645?
Low severity, with a CVSS score of 3.1, published 25 February 2026.
Which products and versions are affected?
changedetection.io (PyPI) ECOSYSTEM:introduced=0,fixed=0.53.7, ECOSYSTEM:introduced=0,fixed=0.54.1.
Is there a fix for CVE-2026-27645?
Yes. changedetection.io (PyPI): upgrade to 0.53.7, 0.54.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
Am I affected by CVE-2026-27645?
Check whether you run changedetection.io (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • changedetection.io (PyPI): upgrade to 0.53.7, 0.54.1 or later
    pip install "changedetection.io>=0.54.1"

Affected products

  • changedetection.io (PyPI) ECOSYSTEM:introduced=0,fixed=0.53.7, ECOSYSTEM:introduced=0,fixed=0.54.1

Identifiers

  • CVE-2026-27645
  • GHSA-mw8m-398g-h89w
  • PYSEC-2026-2125

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.