CVE-2026-69203

high

Http4s is a Scala interface for HTTP services.

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

7.5 (CVSS v3.1)

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Severity source: NVD CVSS v3.1 (security-advisories@github.com)

Timeline (UTC)

Published: 2026-09-15 20:17

Modified: 2026-09-16 20:38

NVD status: Deferred

Last synced 2 days ago

Verified against the source API 2026-10-27 06:53 UTC

Exploitation

Not listed in CISA KEV (as of last catalog sync)

Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).

Affected products

Not reported by the source (unknown — not "none").

Weakness classification (CWE)

CWE-400 CWE-770

Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.

Mitigation & advisories

No vendor advisory or patch reference tagged by NVD. Check the references below.

References

https://github.com/http4s/http4s/commit/4983de1f93f2caaa3b9de310cf6a9db32c50d66e security-advisories@github.com
https://github.com/http4s/http4s/releases/tag/v0.23.35 security-advisories@github.com
https://github.com/http4s/http4s/releases/tag/v1.0.0-M47 security-advisories@github.com
https://github.com/http4s/http4s/security/advisories/GHSA-9vwc-pc8p-253q security-advisories@github.com

Data sources

NVD CVE API 2.0 — fetched 2026-10-27 06:53 UTC · record ↗

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