xwiki-commons: Improper Neutralization of Input During Web Page Generation
CVE-2023-29528 is a critical-severity improper neutralization of input during web page generation vulnerability in xwiki-commons from XWiki, with a CVSS 3.1 base score of 9.0 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, but only if a user takes part, for example by opening a link or file. Affected xwiki-commons versions: >= 4.2-milestone-1, < 14.10. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.28% chance of exploitation within 30 days, higher than 70% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Commons to 14.10 or a later version.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| XWiki | xwiki-commons | >= 4.2-milestone-1, < 14.10 | Not stated |
| XWiki | Commons | 4.3 up to, but not including, 14.10; 4.2 | 14.10 |
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
- RequiredA user must take an action such as opening a file or link.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- 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:R/S:C/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 9.0 | Critical | CNA (github.com) |
| CVSS 3.1 | 9.0 | Critical | NVD |
Official description
XWiki Commons are technical libraries common to several other top level XWiki projects. The "restricted" mode of the HTML cleaner in XWiki, introduced in version 4.2-milestone-1 and massively improved in version 14.6-rc-1, allowed the injection of arbitrary HTML code and thus cross-site scripting via invalid HTML comments. As a consequence, any code relying on this "restricted" mode for security is vulnerable to JavaScript injection ("cross-site scripting"/XSS). When a privileged user with programming rights visits such a comment in XWiki, the malicious JavaScript code is executed in the context of the user session. This allows server-side code execution with programming rights, impacting the confidentiality, integrity and availability of the XWiki instance. This problem has been patched in XWiki 14.10, HTML comments are now removed in restricted mode and a check has been introduced that ensures that comments don't start with `>`. There are no known workarounds apart from upgrading to a version including the fix.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Neutralization of Input During Web Page Generation
The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
How developers prevent this class of flaw
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples of libraries and frameworks that make it easier to generate properly encoded output include Microsoft's Anti-XSS library, the OWASP ESAPI Encoding module, and Apache Wicket.
- Understand all the potential areas where untrusted inputs can enter your software: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls.
- For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
More Improper Neutralization of Input During Web Page Generation vulnerabilities (CWE-79)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Patches and release notes
Other vulnerabilities in xwiki-commons
- 9.3 Critical severity
- 9.8 Critical severity
- 9.6 Critical severity
- 9.0 Critical severity
- 9.9 Critical severity
- 7.5 High severity
Recent Improper Neutralization of Input During Web Page Generation vulnerabilities
- 9.0 Critical severity
- 9.0 Critical severity
- 9.0 Critical severity
- 8.2 High severity
- 9.0 Critical severity
- 9.6 Critical severity
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