GHSA-38rv-x7px-6hhq
undici WebSocket client vulnerable to denial of service via cumulative fragment bypass
Quick fix
GHSA-38rv-x7px-6hhq — undici: upgrade to the fixed version with the command below.
npm install undici@8.5.0Details
## Impact
The undici WebSocket client enforces `maxPayloadSize` per-frame but does not enforce the cumulative size of fragmented uncompressed messages. A malicious WebSocket server can stream many small fragments that each pass per-frame validation but collectively exceed the configured limit, causing unbounded memory growth in the client process. The result is memory exhaustion and a denial of service.
Affected applications are those using the undici WebSocket client (`new WebSocket(...)`) that can be induced to connect to an attacker-controlled or compromised WebSocket endpoint.
This is a regression specific to undici 8.1.0. The 6.25.0 line shipped the equivalent cumulative check from the start and is unaffected. The 7.x line never had the `maxPayloadSize` feature and is also unaffected.
## Patches
Upgrade to undici >= 8.5.0.
## Workarounds
No workaround is available. The fix must be applied through an upgrade.
Are you affected?
Enter the version of the package you're using.