xwiki-platform: Improper Neutralization of Special Elements in Output Used by a Downstream Component
CVE-2023-36470 is a high-severity improper neutralization of special elements in output used by a downstream component vulnerability in xwiki-platform from XWiki, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. Affected xwiki-platform versions: >= 6.2-milestone-1, < 14.10.6. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.93% chance of exploitation within 30 days, higher than 80% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Xwiki to 14.10.6 or a later version.
- Read the advisory on github.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| XWiki | xwiki-platform | >= 6.2-milestone-1, < 14.10.6 | Not stated |
| XWiki | Xwiki | 6.2 up to, but not including, 14.10.6; 15.0; 15.1 | 14.10.6 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 9.9 | Critical | CNA (github.com) |
| CVSS 3.1 | 8.8 | High | NVD |
Official description
XWiki Platform is a generic wiki platform offering runtime services for applications built on top of it. By either creating a new or editing an existing document with an icon set, an attacker can inject XWiki syntax and Velocity code that is executed with programming rights and thus allows remote code execution. There are different attack vectors, the simplest is the Velocity code in the icon set's HTML or XWiki syntax definition. The [icon picker](https://extensions.xwiki.org/xwiki/bin/view/Extension/Icon%20Theme%20Application#HIconPicker) can be used to trigger the rendering of any icon set. The XWiki syntax variant of the icon set is also used without any escaping in some documents, allowing to inject XWiki syntax including script macros into a document that might have programming right, for this the currently used icon theme needs to be edited. Further, the HTML output of the icon set is output as JSON in the icon picker and this JSON is interpreted as XWiki syntax, allowing again the injection of script macros into a document with programming right and thus allowing remote code execution. This impacts the confidentiality, integrity and availability of the whole XWiki instance. This issue has been patched in XWiki 14.10.6 and 15.1. Icon themes now require script right and the code in the icon theme is executed within the context of the icon theme, preventing any rights escalation. A macro for displaying icons has been introduced to avoid injecting the raw wiki syntax of an icon set into another document. Users are advised to upgrade. There are no known workarounds for this vulnerability.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Neutralization of Special Elements in Output Used by a Downstream Component
The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component.
How developers prevent this class of flaw
- Programming languages and supporting technologies might be chosen which are not subject to these issues.
- Utilize an appropriate mix of allowlist and denylist parsing to filter control-plane syntax from all input.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
- github.com/xwiki/xwiki-platform/security/advisories/GHSA-fm68-j7ww-h9xfExploit
- jira.xwiki.org/browse/XWIKI-20524Exploit, Issue Tracking
Patches and release notes
Other vulnerabilities in xwiki-platform
- 7.1 High severity
- 8.2 High severity
- 7.5 High severity
- 9.3 Critical severity
- 8.6 High severity
- 7.5 High severity
Recent Improper Neutralization of Special Elements in Output Used by a Downstream Component vulnerabilities
- 8.8 High severity
- 8.8 High severity
- 9.8 Critical severity
- 7.2 High severity
- 9.8 Critical severity
- 8.8 High severity
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