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CVE-2026-69202

Http4s Ember HTTP/2: unbounded inbound body buffering

CVSS 3.1 7.5 HIGHCheck source for fixed versionsKEV status unknown

Original advisory

cve-program · CVE-2026-69202

Published

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember’s HTTP/2 flow-control window is replenished according to bytes received from the network rather than bytes consumed by the application, while each stream stores DATA in an unbounded channel. A hostile peer can therefore send a body faster than a slow or non-draining application consumes it, retaining payloads in heap on an ember-server or ember-client configured with withHttp2. The patch bounds the per-stream H2Connection body channel so application consumption applies backpressure. This issue is fixed in versions 0.23.35 and 1.0.0-M47.

Read the publisher's advisory

Affected versions, risk and source history

cve-program · CVE-2026-69202

Published

http4s

Vendor product

Publisher's version information

Shown as published. These rules are not interpreted as NuGet package version ranges.

{
                    "vendor": "http4s",
                    "product": "http4s",
                    "versions": [
                        {
                            "version": "< 0.23.35",
                            "status": "affected"
                        },
                        {
                            "version": ">= 1.0.0-M1, < 1.0.0-M47",
                            "status": "affected"
                        }
                    ]
                }

Original source record · Cite this exact observation · Complete original publisher JSON