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Fencer Vulns
medium 6.8

CVE-2023-38490 json

Kirby XML External Entity (XXE) vulnerability in the XML data handler

published 2023-07-27 3 y ago modified 2026-09-10 1 mo ago also GHSA-q386-w6fg-gmgp , EUVD-2023-2124

cvss
6.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.7%
EPSS 1.7% chance of exploitation in 30 days, percentile 77%
public exploits
0
none known

Summary

Kirby is a content management system. A vulnerability in versions prior to 3.5.8.3, 3.6.6.3, 3.7.5.2, 3.8.4.1, and 3.9.6 only affects Kirby sites that use the `Xml` data handler (e.g. `Data::decode($string, 'xml')`) or the `Xml::parse()` method in site or plugin code. The Kirby core does not use any of the affected methods.

XML External Entities (XXE) is a little used feature in the XML markup language that allows to include data from external files in an XML structure. If the name of the external file can be controlled by an attacker, this becomes a vulnerability that can be abused for various system impacts like the disclosure of internal or confidential data that is stored on the server (arbitrary file disclosure) or to perform network requests on behalf of the server (server-side request forgery, SSRF).

Kirby's `Xml::parse()` method used PHP's `LIBXML_NOENT` constant, which enabled the processing of XML external entities during the parsing operation. The `Xml::parse()` method is used in the `Xml` data handler (e.g. `Data::decode($string, 'xml')`). Both the vulnerable method and the data handler are not used in the Kirby core. However they may be used in site or plugin code, e.g. to parse RSS feeds or other XML files. If those files are of an external origin (e.g. uploaded by a user or retrieved from an external URL), attackers may be able to include an external entity in the XML file that will then be processed in the parsing process. Kirby sites that don't use XML parsing in site or plugin code are *not* affected.

The problem has been patched in Kirby 3.5.8.3, 3.6.6.3, 3.7.5.2, 3.8.4.1, and 3.9.6. In all of the mentioned releases, the maintainers have removed the `LIBXML_NOENT` constant as processing of external entities is out of scope of the parsing logic. This protects all uses of the method against the described vulnerability.

Patch / fix

  • packagist getkirby/cms 3.5.8.3, 3.6.6.3, 3.7.5.2, 3.8.4.1, 3.9.6
  • getkirby kirby 3.5.8.3, 3.6.6.3, 3.7.5.2, 3.8.4.1, 3.9.6

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

1.70% chance of exploitation in the next 30 days, higher than 77% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.8 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N
NVD 3.1 10.0 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N
GitHub 3.1 6.8 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
packagist getkirby/cms
<3.5.8.3
>=3.6.0, <3.6.6.3
>=3.7.0, <3.7.5.2
>=3.8.0, <3.8.4.1
>=3.9.0, <3.9.6
3.5.8.3
3.6.6.3
3.7.5.2
3.8.4.1
3.9.6

Affected products

  • getkirby kirby

Classification

Weakness
  • CWE-611 Improper Restriction of XML External Entity Reference
  • CWE-776 Improper Restriction of Recursive Entity References in DTDs

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.