CVE-2026-32870

HIGH
Published Apr 24, 2026 Modified Apr 27, 2026 CWE-91

Description

Kirby is an open-source content management system. 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, prior to versions 4.9.0 and 5.4.0, 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` block. This structured data would then also be allowed to pass through, circumventing the value protection. The `Xml::value()` method is used in `Xml::tag()`, `Xml::create()` and in the `Xml` data handler (e.g. `Data::encode($string, 'xml')`). Both the vulnerable methods and the data handler are not used in the Kirby core. However they may be used in site or plugin code, e.g. to create XML strings from input data. If those generated files are passed to another implementation that assigns specific meaning to the XML schema, manipulation of this system's behavior is possible. Kirby sites that don't use XML generation in site or plugin code are not affected. The problem has been patched in Kirby 4.9.0 and Kirby 5.4.0. In all of the mentioned releases, Kirby has added additional checks that only allow unchanged `CDATA` passthrough if the entire string is made up of valid `CDATA` blocks and no structured data. This protects all uses of the method against the described vulnerability.

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CVSS v3.1 Score

7.5
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

EPSS — Exploit Prediction

0.0004
Probability of exploitation
0.12%
Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-91 CWE-91

Affected Products

Vendor Product
getkirby kirby
getkirby kirby

References

Frequently Asked Questions

What is CVE-2026-32870? +
Kirby is an open-source content management system. 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, prior to versions 4.9.0 and 5.4.0, 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` block. This structured data would then also be allowed to pass through, circumventing the value protection. The `Xml::value()` method is used in `Xml::tag()`, `Xml::create()` and in the `Xml` data handler (e.g. `Data::encode($string, 'xml')`). Both the vulnerable methods and the data handler are not used in the Kirby core. However they may be used in site or plugin code, e.g. to create XML strings from input data. If those generated files are passed to another implementation that assigns specific meaning to the XML schema, manipulation of this system's behavior is possible. Kirby sites that don't use XML generation in site or plugin code are not affected. The problem has been patched in Kirby 4.9.0 and Kirby 5.4.0. In all of the mentioned releases, Kirby has added additional checks that only allow unchanged `CDATA` passthrough if the entire string is made up of valid `CDATA` blocks and no structured data. This protects all uses of the method against the described vulnerability. It has a CVSS v3.1 base score of 7.5 (HIGH).
How severe is CVE-2026-32870? +
CVE-2026-32870 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0004, placing it in the 0th percentile for exploitation probability.
What products are affected by CVE-2026-32870? +
CVE-2026-32870 affects products from getkirby, specifically: kirby. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2026-32870? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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