Kirby has XML injection in its XML creator toolkit
Date: 2026-04
Affected: composer/getkirby/cms, composer/getkirby/cms
Attack vector: other
Category: vulnerability-disclosure
Severity: Medium
CVE: CVE-2026-32870
CWE: CWE-91

### TL;DR This vulnerability only affects Kirby sites that use the `Xml` data handler (e.g. `Data::encode($string, 'xml')`) or the `Xml::create()`, `Xml::tag()` or `Xml::value()` method(s) in site or plugin code. The Kirby core does not use any of the affected methods. If consumers use an affected method and cannot rule out input to these methods controlled by an attacker, Kirby strongly recommends that they update to a patch release. ---- ### Introduction XML strings contain structured data in tags and attributes. Depending on the used XML schema, this data can carry specific meaning that can lead to actions in other systems that parse and act on the XML data. Tags and attributes are detected based on their specific syntax, which includes characters such as `<`, `>`, `"`, and `&`. If these characters are to be used verbatim in text within the XML string, they can be escaped using a `<![CDATA[ ]]>` block. XML injection is an attack on a system generating or parsing XML files. By injecting special characters into input data, XML output with a malicious meaning could be generated by a vulnerable system. ### Impact Kirby's `Xml::value()` method has special handling for `<![CDATA[ ]]>` blocks. If the input value is already valid `CDATA`, it is not escaped a second time but allowed to pass through. However it was possible to trick this check into allowing values that only *contained* a valid `CDATA` block but also contained other structured data outside of the `CDATA` bloc


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Architectural layers (MAESTRO):