CVE-2026-69209
Http4s is a Scala interface for HTTP services.
Impact
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, The shared WebSocket decoder permits unbounded message buffering because defragmentation accumulates fragments without a limit and FrameTranscoder accepts declared lengths up to Int.MaxValue. A remote client that completes a WebSocket handshake against an http4s-blaze-server or http4s-ember-server endpoint can exhaust server memory with oversized frames or fragmented messages. The patched decoder applies a configurable 64 MiB default limit to individual frames and defragmented messages through EmberServerBuilder.withMaxWebSocketMessageSize. This issue is fixed in versions 0.23.35 and 1.0.0-M47.
Affected products
| Product | Affected versions |
|---|---|
| Http4s Is A Scala Interface For HTTP Services. | before 0.23.35 |
Versions were read from the advisory text. No structured product data has been published for this record yet.