GHSA-4qv8-2p9j-2685

Description

### Impact undici's `EventSource` client can be driven to exhaust process memory by a malicious or compromised Server-Sent Events peer. By sending millions of tiny completed `data:` fields with no blank event separator, or a single unfinished line split across many chunks, the parser retains a growing amount of per-field and per-chunk state. The byte-based `maxEventSize` and `maxResponseSize` limits do not bound that retained state, and `maxResponseSize` is enforced on the compressed body before decompression, so a small compressed response can expand into enough retained memory to terminate the process. The application only needs to maintain an `EventSource` connection to an untrusted peer, which controls only the response. Availability is the only impact. ### Patches Upgrade to `6.29.1`, `7.30.1`, or `8.12.2`, which bound the retained EventSource parser state (the number of `data` fields and buffered chunks, the unfinished-line length, and per-field byte totals) independently of the byte limits. ### Workarounds None.