HTML injection in search results via plaintext message highlighting

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

8.2 · CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:L

EPSS

• CVE-2023-30609: 0.62% estimated exploitation activity in the next 30 days; percentile 49.62 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact 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. Cross-site scripting is possible by including resources from recaptcha.net and gstatic.com which are included in the default CSP. Thanks to Cadence Ember for finding the injection and to S1m for finding possible XSS vectors. Patches Version 3.71.0 of the SDK fixes the issue. Workarounds Restarting the client will clear the injection.

Published by the source

25 Apr 2023, 19:48 UTC

Last modified by the source

8 Nov 2023, 04:12 UTC

Source last checked

26 Oct 2026, 12:27 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-xv83-x443-7rmw

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-xv83-x443-7rmw

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2023-30609

Advisory: HTML injection in search results via plaintext message highlighting
IDs: CVE-2023-30609, GHSA-xv83-x443-7rmw
Record: https://patchnext.com/advisories/cve-2023-30609 (revision 2, source checked 26 Oct 2026, 12:27 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.2)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: matrix-react-sdk 3.71.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm matrix-react-sdk: affected < 3.71.0; fixed in 3.71.0

## Suggested inspection (read-only)
- `npm ls matrix-react-sdk --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on matrix-react-sdk.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-xv83-x443-7rmw (OSV record GHSA-xv83-x443-7rmw lists affected ranges: npm matrix-react-sdk >=0 <3.71.0 (fixed))
- Verified: https://github.com/advisories/GHSA-xv83-x443-7rmw (GitHub-reviewed advisory GHSA-xv83-x443-7rmw lists affected ranges: npm matrix-react-sdk >=0 <3.71.0)

Commands are suggestions: review each one before running it.