CVE-2026-69203Http4s Ember HTTP/2: does not enforce SETTINGS_MAX_CONCURRENT_STREAMS
Updated under an hour ago ()
Does this affect you?
It affects http4s. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
Do this next
Free account, 1 product
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.
- CVSS
- 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- CWE-400, CWE-770
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_M
- NVD analysis
- Deferred
- Record last updated
- Sep 15, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
http4s http4s http4s:http4s (from the name) | before 0.23.35; from 1.0.0-M1, < 1.0.0-M47 | CNA record |
References
- https://github.com/http4s/http4s/security/advisories/GHSA-9vwc-pc8p-253qx-refsource-confirm
- https://github.com/http4s/http4s/commit/4983de1f93f2caaa3b9de310cf6a9db32c50d66ex-refsource-misc
- https://github.com/http4s/http4s/releases/tag/v0.23.35x-refsource-misc
- https://github.com/http4s/http4s/releases/tag/v1.0.0-M47x-refsource-misc
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.