CVE-2026-69218
Description
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, When Ember receives an HTTP/2 HEADERS or PUSH_PROMISE frame without END_HEADERS, H2Connection buffers the header block and subsequent CONTINUATION fragments without a size bound. A remote peer can keep an incomplete block open and exhaust heap memory before request decoding, affecting an ember-server or ember-client configured with withHttp2. The remediation tracks accumulated size against SETTINGS_MAX_HEADER_LIST_SIZE derived from EmberServerBuilder.maxHeaderSize or EmberClientBuilder.maxResponseHeaderSize, sends GOAWAY when the limit is exceeded, and applies receiveHeadersTimeout to incomplete blocks. This issue is fixed in versions 0.23.35 and 1.0.0-M47.
How to fix
- org.http4s:http4s-ember-core_2.120.23.35 or later
- org.http4s:http4s-ember-core_2.130.23.35, 1.0.0-M47 or later
- org.http4s:http4s-ember-core_30.23.35, 1.0.0-M47 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| org.http4s:http4s-ember-core_2.12Maven | v < 0.23.35 | 0.23.35 |
| org.http4s:http4s-ember-core_2.13Maven | v < 0.23.35, 1.0.0-M1 ≤ v < 1.0.0-M47 | 0.23.35, 1.0.0-M47 |
| org.http4s:http4s-ember-core_3Maven | v < 0.23.35, 1.0.0-M1 ≤ v < 1.0.0-M47 | 0.23.35, 1.0.0-M47 |
Check your version
Choose the product and enter the version you run to see whether it falls in the affected range.
Attack Surface Management
See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.