CVE-2026-27645

changedetection.io Vulnerable to Reflected XSS in RSS Single Watch Error Response

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

dgtlmoon · changedetection.io

CVSS v3.1 GITHUB

6.1 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS

0.50% chance of exploitation in the next 30 days, 42nd percentile

Nuclei

medium · CWE-79

Published

2026-02-25

Proof-of-concept exploits (1)

• advisories/GHSA-mw8m-398g-h89w

Nuclei templates (1)

• projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-27645.yaml

Security advisories

• dgtlmoon/changedetection.io/security/advisories/GHSA-mw8m-398g-h89w
• dgtlmoon/changedetection.io/commit/a385c89abf44b52fcfa20c7c6a6dd3047c4c1eb5

References

• CVE Record
• NVD entry