CVE-2023-30609 is a medium-severity (CVSS 5.4) vulnerability in matrix-react-sdk. A fix is available for matrix-react-sdk — see the affected versions and patch details below.
matrix-react-sdk vulnerable to HTML injection in search results via plaintext message highlighting
Real-World Exposure
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
matrix-react-sdk is a react-based SDK for inserting a Matrix chat/VoIP client into a web page. Prior to version 3.71.0, plain text messages containing HTML tags are rendered as HTML in the search results. To exploit this, an attacker needs to trick a user into searching for a specific message containing an HTML injection payload. No cross-site scripting attack is possible due to the hardcoded content security policy. Version 3.71.0 of the SDK patches over the issue. As a workaround, restarting the client will clear the HTML injection.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | matrix-react-sdk | all versions | 3.71.0npm install matrix-react-sdk@3.71.0 |
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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update matrix-react-sdk to 3.71.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-30609 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2023-30609 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-30609. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2023-30609 in your dependencies?
O3 Security finds CVE-2023-30609 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.