matrix-js-sdk has insufficient MXC URI validation which allows client-side path traversal

MEDIUM 5.3CVE-2024-50336 · GHSA-xvg8-m4x3-w6xr · Published 12/11/2024 · updated 17/06/2026

In short

CVE-2024-50336 is a MEDIUM (CVSS 5.3) vulnerability affecting matrix-js-sdk.
Chance of exploitation in the next 30 days (EPSS): 0.83%, higher than 57.6% of all vulnerabilities.
Fix: update to 34.11.1 or later.

Package	Affected versions	Patched versions
matrix-js-sdk npm	`< 34.11.1`	`34.11.1`

Description

Summary

matrix-js-sdk before 34.11.0 is vulnerable to client-side path traversal via crafted MXC URIs. A malicious room member can trigger clients based on the matrix-js-sdk to issue arbitrary authenticated GET requests to the client's homeserver.

Details

The Matrix specification demands homeservers to perform validation of the server-name and media-id components of MXC URIs with the intent to prevent path traversal. However, it is not mentioned that a similar check must also be performed on the client to prevent client-side path traversal. matrix-js-sdk fails to perform this validation.

Patches

Fixed in matrix-js-sdk 34.11.1.

Workarounds

None.

References

NVD description

matrix-js-sdk is a Matrix messaging protocol Client-Server SDK for JavaScript. matrix-js-sdk before 34.11.0 is vulnerable to client-side path traversal via crafted MXC URIs. A malicious room member can trigger clients based on the matrix-js-sdk to issue arbitrary authenticated GET requests to the client's homeserver. Fixed in matrix-js-sdk 34.11.1.