Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember’s HTTP/1.1 parser accepts differing duplicate Content-Length headers and uses the last value instead of rejecting the message. When an Ember server is behind a keep-alive intermediary that selects a different occurrence, an unauthenticated attacker can create CL.CL request smuggling that bypasses front-end controls, captures a later user’s headers, or poisons a cache. The shared client parser can also misframe responses from a malicious or compromised upstream when the client acts as a proxy for multiple downstream consumers. This issue is fixed in versions 0.23.35 and 1.0.0-M47.
CVE-2026-69217
HIGHPre-NVD 8.78.7—Trending — 3 sources updated this week
EchelonGraph scoreMEDIUM confidence
This high-severity CVE scores 8.7 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.5%, top 58% 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
8.7EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.7Exploit: None knownExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 8.7
- EG Score
- 8.7(medium)
- EG Risk
- 39(Track)EG Risk 39/100SSVC: 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 computedSeverity87% × 45%Exploitation1% × 40%Automatability0% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 0%
- EPSS %ILE
- 42%
- 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 24e8d34e3ea8 (http4s/http4s)
Patch available: http4s/http4s v0.23.35 (contains commit 24e8d34e3ea8)
https://github.com/http4s/http4s/commit/24e8d34e3ea89f8f23e0053ec9944f6467e8086dgithub Patch Available
Ember Server accepts duplicate Content-Length headers · Advisory · http4s/http4s · GitHub
https://github.com/http4s/http4s/security/advisories/GHSA-p83c-4wj9-p6w9Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 10× in last 7d / 10× 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 18:55 UTCEG score recompute
- 2026-09-18 19:38 UTCEG score recompute
- 2026-09-18 19:28 UTCEPSS rescore
- 2026-09-17 20:21 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 20:40 UTCEG score recompute
- 2026-09-15 19:23 UTCEG score recompute
- 2026-09-15 19:22 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Same CWE
10 shownCWE-444
Frequently asked(5)
What is CVE-2026-69217?
CVE-2026-69217 is a high 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 HTTP/1.1 parser accepts differing duplicate Content-Length headers and uses the last value instead of rejecting the message. When an Ember server is behind a keep-alive intermediary that selects a different…
When was CVE-2026-69217 disclosed?
CVE-2026-69217 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-2026-69217 actively exploited?
CVE-2026-69217 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 58.2% of all scored CVEs.
What is the CVSS score of CVE-2026-69217?
CVE-2026-69217 has a CVSS v3 base score of 8.7 (NVD).
How do I remediate CVE-2026-69217?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-69217, 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
Explore the affected products and dependency analysis for CVE-2026-69217
Is Your Infrastructure Affected by CVE-2026-69217?
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