high7.5
CVE-2026-69203
Http4s Ember HTTP/2 does not enforce SETTINGS_MAX_CONCURRENT_STREAMS
Impact
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, An Ember server with HTTP/2 enabled through withHttp2 does not enforce SETTINGS_MAX_CONCURRENT_STREAMS for peer-created streams. One unauthenticated connection can open an unbounded number of streams, each retaining per-stream state until heap exhaustion. The same unchecked allocation is reachable in an ember-client through server-initiated PUSH_PROMISE frames because enablePush is not enforced. This issue is fixed in versions 0.23.35 and 1.0.0-M47.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| maven | org.http4s:http4s-ember-core_2.12 | <= 0.23.34 | 0.23.35 |
| maven | org.http4s:http4s-ember-core_2.13 | <= 0.23.34 | 0.23.35 |
| maven | org.http4s:http4s-ember-core_3 | <= 0.23.34 | 0.23.35 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-9vwc-pc8p-253q
- https://github.com/http4s/http4s/security/advisories/GHSA-9vwc-pc8p-253q
- https://github.com/http4s/http4s/commit/4983de1f93f2caaa3b9de310cf6a9db32c50d66e
- https://github.com/http4s/http4s/releases/tag/v0.23.35
- https://github.com/http4s/http4s/releases/tag/v1.0.0-M47