Vulnerability Details : CVE-2023-38490
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.
Vulnerability category: XML external entity (XXE) injectionServer-side request forgery (SSRF)
Products affected by CVE-2023-38490
- cpe:2.3:a:getkirby:kirby:*:*:*:*:*:*:*:*
- cpe:2.3:a:getkirby:kirby:*:*:*:*:*:*:*:*
- cpe:2.3:a:getkirby:kirby:*:*:*:*:*:*:*:*
- cpe:2.3:a:getkirby:kirby:*:*:*:*:*:*:*:*
- cpe:2.3:a:getkirby:kirby:*:*:*:*:*:*:*:*
Exploit prediction scoring system (EPSS) score for CVE-2023-38490
0.34%
Probability of exploitation activity in the next 30 days
EPSS Score History
~ 72 %
Percentile, the proportion of vulnerabilities that are scored at or less
CVSS scores for CVE-2023-38490
Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Score Source | First Seen |
---|---|---|---|---|---|---|
10.0
|
CRITICAL | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N |
3.9
|
5.8
|
NIST | |
6.8
|
MEDIUM | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N |
2.2
|
4.0
|
GitHub, Inc. |
CWE ids for CVE-2023-38490
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The product processes an XML document that can contain XML entities with URIs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output.Assigned by: security-advisories@github.com (Primary)
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The product uses XML documents and allows their structure to be defined with a Document Type Definition (DTD), but it does not properly control the number of recursive definitions of entities.Assigned by: security-advisories@github.com (Primary)
References for CVE-2023-38490
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https://github.com/getkirby/kirby/security/advisories/GHSA-q386-w6fg-gmgp
XML External Entity (XXE) vulnerability in the XML data handler · Advisory · getkirby/kirby · GitHubThird Party Advisory
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https://github.com/getkirby/kirby/releases/tag/3.6.6.3
Release 3.6.6.3 · getkirby/kirby · GitHubThird Party Advisory
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https://github.com/getkirby/kirby/commit/277b05662d2b67386f0a0f18323cf68b30e86387
Fix XXE vulnerability · getkirby/kirby@277b056 · GitHubPatch;Third Party Advisory
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https://github.com/getkirby/kirby/releases/tag/3.7.5.2
Release 3.7.5.2 · getkirby/kirby · GitHubThird Party Advisory
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https://github.com/getkirby/kirby/releases/tag/3.5.8.3
Release 3.5.8.3 · getkirby/kirby · GitHubThird Party Advisory
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https://github.com/getkirby/kirby/releases/tag/3.9.6
Release 3.9.6 · getkirby/kirby · GitHubThird Party Advisory
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https://github.com/getkirby/kirby/releases/tag/3.8.4.1
Release 3.8.4.1 · getkirby/kirby · GitHubThird Party Advisory
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