Answer in brief
CVE-2026-69213 records a High severity (CVSS 7.5) vulnerability in Http4s Ember HTTP/2: unbounded outbound frame queue. 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, Ember HTTP/2 serializes outbound frames through one unbounded queue consumed by writeLoop. When the peer stops reading, an unauthenticated HTTP/2 client can continue sending PING, SETTINGS, or DATA frames that cause Ember to enqueue acknowledgments or WINDOW_UPDATE frames faster than the writer drains them, exhausting heap memory on a server built with withHttp2. The shared behavior also affects an ember-client connected to a hostile HTTP/2 server, and the patch replaces the unbounded path with bounded, backpressured outbound queues. This issue is fixed in versions 0.23.35 and 1.0.0-M47.
Quoted source text, attributed separately from HOL analysis.