GHSA-42fh-pvvh-999x — xwiki-platform-messagestr…
MEDIUMGHSA-42fh-pvvh-999x is a medium-severity (CVSS 4.7) CWE-668 vulnerability in org.xwiki.platform:xwiki-platform-messagestream. No vendor fix is recorded yet; mitigation options are listed below.
Unregistered users can see "public" messages from a closed wiki via notifications from a different wiki
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for GHSA-42fh-pvvh-999x.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-42fh-pvvh-999x plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 379,145 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
org.xwiki.platform:xwiki-platform-messagestreamReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
Impact
This vulnerability impacts users of a subwiki of XWiki where Message Stream is enabled and use, if they configured their wiki to be closed by selecting "Prevent unregistered users to view pages" in the Administrations Rights.
The vulnerability is that any message sent in a subwiki to "everyone" is actually sent to the farm: any visitor of the main wiki will be able to see that message through the Dashboard, even if the subwiki is configured to be private.
Patches
This problem has not been patched and is not going to be patched in the future: Message Stream has been deprecated in XWiki 16.8.0RC1 and is not maintained anymore.
Workarounds
Message Stream is disabled by default, it's advised to keep it disabled from Administration > Social > Message Stream.
References
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.xwiki.platform:xwiki-platform-messagestream | ≥ 5.0 | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.xwiki.platform:xwiki-platform-messagestream, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
No patched version of org.xwiki.platform:xwiki-platform-messagestream has shipped for GHSA-42fh-pvvh-999x yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-42fh-pvvh-999x can be triaged on real exposure rather than presence alone.
Tailored to GHSA-42fh-pvvh-999x. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-42fh-pvvh-999x in your dependencies?
O3 Security finds GHSA-42fh-pvvh-999x across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.