CVE-2026-69213
Description
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember HTTP/2 serializes outbound frames through one unbounded queue consumed by writeLoop. When the peer stops reading, an unauthenticated HTTP/2 client can continue sending PING, SETTINGS, or DATA frames that cause Ember to enqueue acknowledgments or WINDOW_UPDATE frames faster than the writer drains them, exhausting heap memory on a server built with withHttp2. The shared behavior also affects an ember-client connected to a hostile HTTP/2 server, and the patch replaces the unbounded path with bounded, backpressured outbound queues. This issue is fixed in versions 0.23.35 and 1.0.0-M47.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
org.http4s:http4s-ember-core_2.12Maven | < 0.23.35 | 0.23.35 |
org.http4s:http4s-ember-core_2.13Maven | < 0.23.35 | 0.23.35 |
org.http4s:http4s-ember-core_3Maven | < 0.23.35 | 0.23.35 |
org.http4s:http4s-ember-core_3Maven | >= 1.0.0-M1, < 1.0.0-M47 | 1.0.0-M47 |
org.http4s:http4s-ember-core_2.13Maven | >= 1.0.0-M1, < 1.0.0-M47 | 1.0.0-M47 |
Affected products
2Patches
Vulnerability mechanics
References
5- github.com/advisories/GHSA-8f3q-3jmv-7prwghsaADVISORY
- github.com/http4s/http4s/commit/13fe24d6440bde2f1eb70121486cf59c278e6baenvdWEB
- github.com/http4s/http4s/releases/tag/v0.23.35nvdWEB
- github.com/http4s/http4s/releases/tag/v1.0.0-M47nvdWEB
- github.com/http4s/http4s/security/advisories/GHSA-8f3q-3jmv-7prwnvdWEB
News mentions
1- Http4s: Batch of 18 CVEs Disclosed, Featuring Critical HTTP/1.1 and HTTP/2 FlawsVypr Intelligence · Sep 15, 2026