Vulnerability · Published Feb 25, 2026 · Assigned by GitHub_M
CVE-2026-27645changedetection.io Vulnerable to Reflected XSS in RSS Single Watch Error Response
Medium 6.1
In plain English
A medium-severity cross-site scripting in changedetection.io from dgtlmoon. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 43% of all known vulnerabilities). Ready-made attack tooling exists: Nuclei. Fixed versions are available - upgrade the affected package.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| PyPI | changedetection-io | 0.53.7 | GHSA-mw8m-398g-h89w |
| PyPI | changedetection-io | 0.54.1 | PYSEC-2026-2125 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| dgtlmoon | changedetection.io | < 0.54.1 |
Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N