CVE-2026-69203
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.
Scoring
- Severity
- HIGH
- CVSS base score
- 7.5
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS probability
- 0.46%
- CWE
- CWE-400, CWE-770
- Published
- 2026-09-15
- Last modified
- 2026-09-15
Affected products
- http4s http4s
- http4s http4s
Weakness type
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