Package Instance

Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
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.

Malicious homeservers can steal message keys when the matrix-react-sdk user invites another user to a room
### Impact

matrix-react-sdk before 3.102.0 allows a malicious homeserver to potentially steal message keys for a room when a user invites another user to that room, via injection of a malicious device controlled by the homeserver. This is possible because matrix-react-sdk before 3.102.0 shared historical message keys on invite.

### Patches

matrix-react-sdk 3.102.0 [disables sharing message keys on invite](https://github.com/matrix-org/matrix-react-sdk/pull/12618) by removing calls to the vulnerable functionality.

### Workarounds

None.

### References

The vulnerability in matrix-react-sdk is caused by calling `MatrixClient.sendSharedHistoryKeys` in matrix-js-sdk, which is inherently vulnerable to this sort of attack. This matrix-js-sdk vulnerability is tracked as CVE-2024-47080 / [GHSA-4jf8-g8wp-cx7c](https://github.com/matrix-org/matrix-js-sdk/security/advisories/GHSA-4jf8-g8wp-cx7c). Given that this functionality is not specific to sharing message keys on *invite*, is optional, has to be explicitly called by the caller and has been independently patched in matrix-react-sdk by removing the offending calls, we believe it is proper to treat the matrix-react-sdk vulnerability as a separate one, with its own advisory and CVE.

The matrix-org/matrix-react-sdk repository has recently been archived and the project was moved to [element-hq/matrix-react-sdk](https://github.com/element-hq/matrix-react-sdk). Given that this happened *after* the first patched release, no releases of the project on [element-hq/matrix-react-sdk](https://github.com/element-hq/matrix-react-sdk) were ever vulnerable to this vulnerability.

Patching pull request: https://github.com/matrix-org/matrix-react-sdk/pull/12618.

### For more information

If you have any questions or comments about this advisory, please email us at security at [security at matrix.org](mailto:security@matrix.org).

Matrix SDK for React's URL preview setting for a room is controllable by the homeserver
### 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](https://nvd.nist.gov/vuln-metrics/cvss/v3-calculator?vector=AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:N/A:N&version=3.1)) 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.

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
matrix-react-sdk is a react-based SDK for inserting a Matrix chat/voip client into a web page. The Export Chat feature includes certain attacker-controlled elements in the generated document without sufficient escaping, leading to stored Cross site scripting (XSS). Since the Export Chat feature generates a separate document, an attacker can only inject code run from the `null` origin, restricting the impact. However, the attacker can still potentially use the XSS to leak message contents. A malicious homeserver is a potential attacker since the affected inputs are controllable server-side. This issue has been addressed in commit `22fcd34c60` which is included in release version 3.76.0. Users are advised to upgrade. The only known workaround for this issue is to disable or to not use the Export Chat feature.