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.
CVE-2026-69216
MEDIUMPre-NVD 5.45.4—Trending — 3 sources updated this week
EchelonGraph scoreMEDIUM confidence
This medium-severity CVE scores 5.4 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 84% 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).
Triggered by: NVD CVSS baseline
Sources: epss, secondary
5.4EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.4Exploit: None knownExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 5.4
- EG Score
- 5.4(medium)
- EG Risk
- 24(Track)EG Risk 24/100SSVC: 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 computedSeverity54% × 45%Exploitation0% × 40%Automatability0% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 0%
- EPSS %ILE
- 16%
- KEV
- Not listed
Published
September 15, 2026
Last Modified
September 16, 2026
Advisory Details (4)
Auto-updated Sep 15, 2026Patch available. Sources: github, github_commit, github_release.
github_release Patch Available
v1.0.0-M47
Patch available: http4s/http4s v1.0.0-M47 (pre-release)
https://github.com/http4s/http4s/releases/tag/v1.0.0-M47github_release Patch Available
v0.23.35
Patch available: http4s/http4s v0.23.35
https://github.com/http4s/http4s/releases/tag/v0.23.35github_commit Patch Available
commit d78612a5abd5 (http4s/http4s)
Patch available: http4s/http4s v0.23.35 (contains commit d78612a5abd5)
https://github.com/http4s/http4s/commit/d78612a5abd5a2547487598d3342be05573e16f0github Patch Available
Ember chunk parser lenience (TE.TE request smuggling) · Advisory · http4s/http4s · GitHub
https://github.com/http4s/http4s/security/advisories/GHSA-jrpm-956j-96jgVendor Advisories for CVE-2026-69216(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(1)
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.
- 2026-09-18 20:12 UTCEG score recompute
- 2026-09-18 19:28 UTCEPSS rescore
- 2026-09-17 20:38 UTCEG score recompute
- 2026-09-16 14:25 UTCEG score recompute
- 2026-09-16 14:08 UTCEPSS rescore
- 2026-09-16 14:01 UTCEG score recompute
- 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-2026-69216?
CVE-2026-69216 is a medium vulnerability published on September 15, 2026. 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…
When was CVE-2026-69216 disclosed?
CVE-2026-69216 was first published in the National Vulnerability Database on September 15, 2026, with the most recent update on September 16, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-69216 actively exploited?
CVE-2026-69216 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 84.3% of all scored CVEs.
What is the CVSS score of CVE-2026-69216?
CVE-2026-69216 has a CVSS v3 base score of 5.4 (NVD).
How do I remediate CVE-2026-69216?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-69216, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-69216
Is Your Infrastructure Affected by CVE-2026-69216?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.