# CVE-2026-69218

## Summary

- **CVE ID:** CVE-2026-69218
- **Severity:** HIGH
- **CVSS Score:** 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
- **CWE:** CWE-770
- **Published:** Sep 15, 2026
- **Last Modified:** Sep 17, 2026

## 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.

## Affected Products

- http4s — http4s (< 0.23.35)
- http4s — http4s (>= 1.0.0-M1, < 1.0.0-M47)

## References

- [CNA](https://github.com/http4s/http4s/security/advisories/GHSA-cp4q-fqw9-4hf6)
- [CNA](https://github.com/http4s/http4s/commit/6e8eccd64a6a74ab4811897881e95e0e1b3a818e)
- [CNA](https://github.com/http4s/http4s/commit/f9dcca4f5a17992ac0972fafd7920f9bc12cdc51)
- [CNA](https://github.com/http4s/http4s/releases/tag/v0.23.35)
- [CNA](https://github.com/http4s/http4s/releases/tag/v1.0.0-M47)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.46%
- **EPSS Percentile:** 39.0

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._