GHSA-f83w-wqhc-cfp4
MEDIUMMatrix SDK for React's URL preview setting for a room is controllable by the homeserver
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.
Blast Radius
matrix-react-sdkReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.
Description
Impact
A malicious homeserver could manipulate a user's account data to cause the client to enable URL previews in end-to-end encrypted rooms, in which case any URLs in encrypted messages would be sent to the server.
Even if the CVSS score would be 4.1 (AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:N/A:N) the maintainer classifies this as High severity issue.
Patches
This was patched in matrix-react-sdk 3.105.1.
Workarounds
Deployments that trust their homeservers, as well as closed federations of trusted servers, are not affected.
References
N/A.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | matrix-react-sdk | all versions | 3.105.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for matrix-react-sdk. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update matrix-react-sdk to 3.105.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-f83w-wqhc-cfp4 is resolved across your whole dependency graph.
Workarounds
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 pinpoints whether GHSA-f83w-wqhc-cfp4 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-f83w-wqhc-cfp4. 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-f83w-wqhc-cfp4 in your dependencies?
O3 detects GHSA-f83w-wqhc-cfp4 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.