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

Source: https://junglewise.ai/threats/cve-2026-27645-changedetection-io-vulnerable-to-reflected-xss-in-rss-single  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-02-25  
License: CC BY 4.0 with a link back

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)](https://junglewise.ai/threats/technologies/changedetection-io). Vendors: [PyPI](https://junglewise.ai/threats/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

  ```sh
  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

## Related threats

- [dgtlmoon changedetection.io path traversal in static content route](https://junglewise.ai/threats/cve-2026-25527-dgtlmoon-changedetection-io-path-traversal-in-static-content)
- [PYSEC-2026-1241 - ChangeDetection.io XSS in watch overview](https://junglewise.ai/threats/cve-2025-52558-changedetection-io-xss-in-watch-overview)
- [PYSEC-2026-1242 - changedetection.io Vulnerable to Improper Input Validation Leading to LFR/Path Traversal](https://junglewise.ai/threats/cve-2024-56509-changedetection-io-vulnerable-to-improper-input-validation)
- [PYSEC-2026-1239 - changedetection.io path traversal using file URI scheme without supplying hostname](https://junglewise.ai/threats/cve-2024-51998-changedetection-io-path-traversal-using-file-uri-scheme-without)
- [PYSEC-2026-1240 - changedetection.io Path Traversal](https://junglewise.ai/threats/cve-2024-51483-changedetection-io-path-traversal)