Summary
XSS Cross Site Scripting
Workarounds
There is no easy workaround except upgrading XWiki.
References
https://jira.xwiki.org/browse/XWIKI-17374
For more information
If you have any questions or comments about this advisory:
- Open an issue in Jira XWiki
- Email us at our security mailing list
Impact
It is possible to persistently inject scripts in XWiki.
For unregistred users:
- By filling simple text fields
For registered users:
- By filling their personal information
- (if they have edit rights) By filling the values of static lists using App Within Minutes
That can lead to user's session hijacking, and if used in conjunction with a social engineering attack it can also lead to disclosure of sensitive data, CSRF attacks and other security vulnerabilities.
That can also lead to the attacker taking over an account.
If the victim has administrative rights it might even lead to code execution on the server, depending on the application and the privileges of the account.
Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.
CVE-2021-29459 has a CVSS score of 9.6 (Critical). The vector is network-reachable, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (12.6.3, 12.8); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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It has been patched on XWiki 12.8 and 12.6.3.
Frequently Asked Questions
- What is CVE-2021-29459? CVE-2021-29459 is a critical-severity cross-site scripting (XSS) vulnerability in org.xwiki.platform:xwiki-platform-oldcore (maven), affecting versions < 12.6.3. It is fixed in 12.6.3, 12.8. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
- How severe is CVE-2021-29459? CVE-2021-29459 has a CVSS score of 9.6 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which packages are affected by CVE-2021-29459?
org.xwiki.platform:xwiki-platform-oldcore(maven) (versions < 12.6.3)org.xwiki.platform:xwiki-platform-web(maven) (versions < 12.6.3)
- Is there a fix for CVE-2021-29459? Yes. CVE-2021-29459 is fixed in 12.6.3, 12.8. Upgrade to this version or later.
- Is CVE-2021-29459 exploitable, and should I be worried? Whether CVE-2021-29459 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2021-29459 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2021-29459?
- Upgrade
org.xwiki.platform:xwiki-platform-oldcoreto 12.6.3 or later - Upgrade
org.xwiki.platform:xwiki-platform-oldcoreto 12.8 or later - Upgrade
org.xwiki.platform:xwiki-platform-webto 12.6.3 or later - Upgrade
org.xwiki.platform:xwiki-platform-webto 12.8 or later
- Upgrade