Answer in brief
CVE-2026-69203 records a High severity (CVSS 7.5) vulnerability in Http4s Ember HTTP/2: does not enforce SETTINGS_MAX_CONCURRENT_STREAMS. The current sources do not mark it as known exploited. The current feed maps http4s/http4s (generic), org.http4s:http4s-ember-core_2.12 (maven), org.http4s:http4s-ember-core_2.13 (maven), org.http4s:http4s-ember-core_2.13 (maven) and additional mapped packages. Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps http4s/http4s (generic), org.http4s:http4s-ember-core_2.12 (maven), org.http4s:http4s-ember-core_2.13 (maven), org.http4s:http4s-ember-core_2.13 (maven) and additional mapped packages. Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| http4s/http4sgeneric | < 0.23.35 || >= 1.0.0-M1, < 1.0.0-M47 | Not reported |
| org.http4s:http4s-ember-core_2.12maven | <=0.23.34 | 0.23.35 |
| org.http4s:http4s-ember-core_2.13maven | <=0.23.34 | 0.23.35 |
| org.http4s:http4s-ember-core_2.13maven | >=1.0.0-M1,<=1.0.0-M46 | 1.0.0-M47 |
| org.http4s:http4s-ember-core_3maven | <=0.23.34 | 0.23.35 |
| org.http4s:http4s-ember-core_3maven | >=1.0.0-M1,<=1.0.0-M46 | 1.0.0-M47 |
Published upstream
Sep 15, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 15, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Sep 15, 2026
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.
Quoted source text, attributed separately from HOL analysis.