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Full vulnerability report · 2023
CVE-2023-38490High confidence

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

getkirby · kirby

6.8MediumCVSS 3.1
Recommended action
Scheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2023-2124

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionScheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
01

What, why and how

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.

What

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.

Why

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.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

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.

Why

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.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Improper Restriction of XML External Entity Reference → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
High: exploitation depends on specific conditions
Security boundary
Changed: exploitation can affect a different security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-611

CWE-611: Improper Restriction of XML External Entity Reference. 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.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACHighAttack complexity: Successful exploitation depends on specific conditions outside the attacker's direct control.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SChangedScope: The attack can affect a component governed by a different security authority.CHighConfidentiality impact: A successful attack can cause a major loss.INoneIntegrity impact: No direct loss is represented by this metric.ANoneAvailability impact: No direct loss is represented by this metric.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedCWE-611
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
< 3.5.8.3; >= 3.6.0, < 3.6.6.3; >= 3.7.0, < 3.7.5.2; >= 3.8.0, < 3.8.41; >= 3.9.0, < 3.9.6
Fixed
An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 27 Jul 2023 · Last source change 16 Oct 2024, 20:31 UTC · CWE-611 · Improper Restriction of XML External Entity Reference

CVE recordCVE.org · 5.1
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2023-2124
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD modified after enrichment

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates →

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2023-38490 · cve.blacktree.nl