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.
CVE-2026-69213
This high-severity CVE scores 7.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 70% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- High severity, but no confirmed exploitation yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 7.5
- EG Score
- 7.5(medium)
- EG Risk
- 49(Track)EG Risk 49/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity75% × 45%Exploitation0% × 40%Automatability100% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 0%
- EPSS %ILE
- 30%
- KEV
- Not listed
Published
September 15, 2026
Last Modified
September 17, 2026
Advisory Details (4)
Auto-updated Sep 15, 2026v1.0.0-M47
Patch available: http4s/http4s v1.0.0-M47 (pre-release)
https://github.com/http4s/http4s/releases/tag/v1.0.0-M47v0.23.35
Patch available: http4s/http4s v0.23.35
https://github.com/http4s/http4s/releases/tag/v0.23.35commit 13fe24d6440b (http4s/http4s)
Patch available: http4s/http4s v0.23.35 (contains commit 13fe24d6440b)
https://github.com/http4s/http4s/commit/13fe24d6440bde2f1eb70121486cf59c278e6baeEmber HTTP/2: unbounded outbound frame queue · Advisory · http4s/http4s · GitHub
https://github.com/http4s/http4s/security/advisories/GHSA-8f3q-3jmv-7prwVendor Advisories for CVE-2026-69213(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Affected Packages
(3 across 1 ecosystem)
Maven(3)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| org.http4s:http4s-ember-core_2.12 | 0.10.0-M10 ... 0.23.9 (114 versions) | 0.23.35 | — |
| org.http4s:http4s-ember-core_2.13 | 0.10.0-M10 ... 0.23.9 (114 versions) | 0.23.35 | — |
| org.http4s:http4s-ember-core_3 | 0.22.0 ... 0.23.9 (58 versions) | 0.23.35 | — |
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 9× in last 7d / 9× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-09-19 06:10 UTCEG score recompute
- 2026-09-18 19:28 UTCEPSS rescore
- 2026-09-18 06:08 UTCEG score recompute
- 2026-09-17 18:08 UTCEG score recompute
- 2026-09-16 19:37 UTCEG score recompute
- 2026-09-16 14:08 UTCEPSS rescore
- 2026-09-15 19:32 UTCEG score recompute
- 2026-09-15 19:13 UTCEG score recompute
- 2026-09-15 19:12 UTCMITRE cvelistV5first tracked
Frequently asked(5)
What is CVE-2026-69213?
When was CVE-2026-69213 disclosed?
Is CVE-2026-69213 actively exploited?
What is the CVSS score of CVE-2026-69213?
How do I remediate CVE-2026-69213?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-69213
Is Your Infrastructure Affected by CVE-2026-69213?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.