CVE-2026-69203CWE-400CWE-770denial-of-service

CVE-2026-69203

High · published September 16, 2026

CVSS v3.1
7.5
EPSS
1%
Percentile
49.5
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
7.5 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v4.0
Not supplied
EPSS
0.00630 · 49.5th percentile
Weaknesses
CWE-400 · Uncontrolled Resource Consumption; CWE-770 · Allocation of Resources Without Limits or Throttling
Published
2026-09-16T00:17Z
References (4)
https://github.com/http4s/http4s/commit/4983de1f93f2caaa3b9de310cf6a9db32c50d66e · [email protected]https://github.com/http4s/http4s/releases/tag/v0.23.35 · [email protected]https://github.com/http4s/http4s/releases/tag/v1.0.0-M47 · [email protected]https://github.com/http4s/http4s/security/advisories/GHSA-9vwc-pc8p-253q · [email protected]
EPSS history
Timeline
  • 17 SEP 03:32Z
    EPSS moved — → 0%
    epss
  • 15 SEP 19:21Z
    Http4s Ember HTTP/2: does not enforce SETTINGS_MAX_CONCURRENT_STREAMS
    cvelistv5