changedetection.io project has an XXE vulnerability
Date: 2026-05
Affected: pip/changedetection.io
Attack vector: other
Category: vulnerability-disclosure
Severity: High
CVE: CVE-2026-41895
CWE: CWE-611
CVSS: 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N)

# changedetection.io_XXE_01 Vulnerability Report: We discovered a XXE vulnerability in the changedetection.io project While analyzing the code logic, it was determined that an area may lead to unintended behavior under specific conditions. With the project's security in mind, see the analysis results to discern whether this may indicate a potential security risk. ## Overview - SOURCE_VERSION: `0.54.9 (9f3a9fdc18bba404244801e5df8109e213ce9ff4)` - Vulnerability type: `XXE` - Finding title: `XML XPath helpers parse untrusted XML with entity resolution left to lxml defaults` - Affected location: `changedetectionio/html_tools.py:287` ## Root Cause `xpath_filter()` switches to XML mode for XML/RSS content and creates `etree.XMLParser(strip_cdata=False)` without explicitly disabling external entity resolution, external DTD loading, or network-backed entity lookup. The helper then parses untrusted XML bytes directly with `etree.fromstring(...)`. ## Source-to-Sink Chain 1. Untrusted XML/RSS response content is fetched from monitored URLs. 2. Stream detection marks the content as XML/RSS and the include-filter path invokes `xpath_filter(..., is_xml=True)`. 3. `xpath_filter()` builds the default XML parser and calls `etree.fromstring(...)` at `changedetectionio/html_tools.py:287`. 4. External entity declarations in attacker XML can be expanded by parser-default behavior in affected runtime combinations. ## Exploitation Preconditions 1. Attacker controls the watched XML/RSS response


Mitigations:

Architectural layers (MAESTRO):