CVE-2023-29528
📋 TL;DR
This vulnerability allows cross-site scripting (XSS) via invalid HTML comments in XWiki's restricted HTML cleaner mode. When exploited, it enables JavaScript injection that can lead to server-side code execution with programming rights. Any XWiki instance using affected versions with privileged users is vulnerable.
💻 Affected Systems
- XWiki Commons
- XWiki Platform
📦 What is this software?
Commons by Xwiki
Commons by Xwiki
Commons by Xwiki
Commons by Xwiki
Commons by Xwiki
Commons by Xwiki
⚠️ Risk & Real-World Impact
Worst Case
Privileged attacker gains full control of XWiki instance, leading to data theft, system compromise, and complete loss of confidentiality, integrity, and availability.
Likely Case
Privileged user with programming rights triggers XSS payload, allowing server-side code execution and potential lateral movement within the XWiki environment.
If Mitigated
With proper input validation and output encoding, the risk is reduced, but the core vulnerability remains until patched.
🎯 Exploit Status
Exploitation requires a privileged user to visit malicious content, but the technical complexity of the XSS injection is low.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: XWiki 14.10
Vendor Advisory: https://github.com/xwiki/xwiki-commons/security/advisories/GHSA-x37v-36wv-6v6h
Restart Required: Yes
Instructions:
1. Backup your XWiki instance. 2. Upgrade to XWiki 14.10 or later. 3. Restart the XWiki application server. 4. Verify the patch is applied by checking the version.
🔧 Temporary Workarounds
No known workarounds
allThe vendor states there are no known workarounds apart from upgrading to a patched version.
🧯 If You Can't Patch
- Restrict access to XWiki to only trusted users and monitor privileged user activities closely.
- Implement web application firewall (WAF) rules to block HTML comment injection patterns.
🔍 How to Verify
Check if Vulnerable:
Check XWiki version: if between 4.2-milestone-1 and 14.9, the system is vulnerable.Check Version:
Check XWiki administration panel or view the XWiki version file in the installation directory.Verify Fix Applied:
Verify XWiki version is 14.10 or higher and test HTML comment handling in restricted mode.📡 Detection & Monitoring
Log Indicators:
- Unusual HTML comment patterns in user inputs
- Privileged user accessing pages with suspicious content
Network Indicators:
- HTTP requests containing malformed HTML comments in parameters
SIEM Query:
Search for patterns like '<!--' followed by JavaScript code in web application logs.🔗 References
- https://github.com/xwiki/xwiki-commons/commit/8ff1a9d7e5d7b45b690134a537d53dc05cae04ab
- https://github.com/xwiki/xwiki-commons/security/advisories/GHSA-x37v-36wv-6v6h
- https://jira.xwiki.org/browse/XCOMMONS-2568
- https://jira.xwiki.org/browse/XWIKI-20348
- https://github.com/xwiki/xwiki-commons/commit/8ff1a9d7e5d7b45b690134a537d53dc05cae04ab
- https://github.com/xwiki/xwiki-commons/security/advisories/GHSA-x37v-36wv-6v6h
- https://jira.xwiki.org/browse/XCOMMONS-2568
- https://jira.xwiki.org/browse/XWIKI-20348
