CVE-2026-69203

Summary

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 Software

VendorProductVersion RangeStatus
http4shttp4s< 0.23.35affected
http4shttp4s>= 1.0.0-M1, < 1.0.0-M47affected

Weaknesses

  • CWE-400: CWE-400: Uncontrolled Resource Consumption
  • CWE-770: CWE-770: Allocation of Resources Without Limits or Throttling

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: yes
    • Technical Impact: partial

References