GHSA-8f3q-3jmv-7prw is a high-severity (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in org.http4s:http4s-ember-core_2.12. O3 Security confirms whether GHSA-8f3q-3jmv-7prw is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Http4s Ember HTTP/2 has an unbounded outbound frame queue
Real-World Exposure
org.http4s:http4s-ember-core_2.12☕org.http4s:http4s-ember-core_2.13☕org.http4s:http4s-ember-core_3☕org.http4s:http4s-ember-core_3☕org.http4s:http4s-ember-core_2.13Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
Ember's HTTP/2 connection serializes all outgoing frames through a single unbounded queue drained by one writer fiber (writeLoop). When the write side stalls, any frames the connection keeps producing accumulate in that queue without limit. The peer can drive this cheaply because the connection emits a control frame in response to inbound frames it does not flow-control: one PING ACK per PING, one SETTINGS ACK per SETTINGS, and a WINDOW_UPDATE per inbound DATA. A single unauthenticated connection can therefore exhaust heap and OOM the process.
This affects an ember server (malicious client) and an ember client (malicious/compromised server that floods the client and stops reading its ACKs).
Impact
Unauthenticated remote denial of service (OOM) against any ember server built .withHttp2, from a single connection, at negligible attacker cost (tiny control frames). Also affects an ember client talking to a hostile HTTP/2 server.
Preconditions
- Ember server or client built
.withHttp2, speaking to a hostile or compromised peer.
Workarounds
- Disable HTTP/2 (do not call
.withHttp2).
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.http4s:http4s-ember-core_2.12 | all versions | 0.23.35 |
| ☕Maven | org.http4s:http4s-ember-core_2.13 | all versions | 0.23.35 |
| ☕Maven | org.http4s:http4s-ember-core_3 | all versions | 0.23.35 |
| ☕Maven | org.http4s:http4s-ember-core_3 | ≥ 1.0.0-M1&&< 1.0.0-M47 | 1.0.0-M47 |
| ☕Maven | org.http4s:http4s-ember-core_2.13 | ≥ 1.0.0-M1&&< 1.0.0-M47 | 1.0.0-M47 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.http4s:http4s-ember-core_2.12. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update org.http4s:http4s-ember-core_2.12 to 0.23.35 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-8f3q-3jmv-7prw is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-8f3q-3jmv-7prw is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-8f3q-3jmv-7prw. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-8f3q-3jmv-7prw in your dependencies?
O3 detects GHSA-8f3q-3jmv-7prw across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.