CVE-2026-69216 is a medium-severity (CVSS 5.4) CWE-444 vulnerability in org.http4s:http4s-ember-core_2.12. O3 Security confirms whether CVE-2026-69216 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Http4s: Ember chunk parser lenience (TE.TE request smuggling)
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_2.13☕org.http4s:http4s-ember-core_3Real-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
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember’s chunk decoder trims the chunk-size token and accepts leading plus or minus signs instead of requiring one or more hexadecimal digits followed by the required CRLF. When an intermediary forwards chunked data without re-encoding and interprets malformed chunk boundaries differently, an unauthenticated attacker can create TE.TE request smuggling that bypasses intermediary controls, poisons caches, or hijacks the request queue. The same response-path leniency can enable response smuggling against an ember-client used as a gateway when the upstream is malicious or compromised. This issue is fixed in versions 0.23.35 and 1.0.0-M47.
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_2.13 | ≥ 1.0.0-M1&&< 1.0.0-M47 | 1.0.0-M47 |
| ☕Maven | org.http4s:http4s-ember-core_3 | ≥ 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 CVE-2026-69216 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 CVE-2026-69216 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 CVE-2026-69216. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-69216 in your dependencies?
O3 detects CVE-2026-69216 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.