EUVD-2026-79025
GHSA-8h4c-x2wg-6xp8
Severity by source
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Primary rating from Vendor (GitHub_M) · only source for this CVE.
CVSS VectorVendor: GitHub_M
Lifecycle Timeline
5Blast Radius
ecosystem impact- 3 maven packages depend on org.http4s:http4s-ember-core_2.12 (2 direct, 1 indirect)
Ecosystem-wide dependent count for version 0.23.35.
DescriptionCVE.org
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember HTTP/1.1 does not reject messages containing both Transfer-Encoding and Content-Length, so an intermediary and Ember can select different body framing rules. When ember-server is behind a keep-alive intermediary that forwards both headers and frames by Content-Length, an unauthenticated attacker can smuggle a second request, bypass intermediary access controls, poison caches, or cause a victim request to be joined to an attacker-controlled prefix. The shared response parser can also desynchronize an ember-client connection when a malicious or compromised upstream sends both headers. This issue is fixed in versions 0.23.35 and 1.0.0-M47.
Analysis
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember HTTP/1.1 does not reject messages containing both Transfer-Encoding and Content-Length, so an intermediary and Ember can select different body framing rules. …
Unlock full vulnerability intelligence
- Risk assessment & exploitation conditions
- Attack chain visualization
- Remediation with exact patch versions
- Threat intelligence from 22 sources
- Personal watchlist & email alerts
Free forever · No credit card required
Threat intelligence, references, and detailed analysis are available after sign-in.
Http4s is a Scala interface for HTTP services. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploita
Http4s is a minimal, idiomatic Scala interface for HTTP services. Rated critical severity (CVSS 9.1), this vulnerability
HTTP request smuggling in http4s Ember (all releases prior to 0.23.35 and 1.0.0-M47) lets an unauthenticated remote atta
Let me synthesize. CVE-2026-69205: http4s Ember HTTP parser request smuggling via Transfer-Encoding header case-sensiti
http4s is an open source scala interface for HTTP. Rated medium severity (CVSS 4.7), this vulnerability is remotely expl
Unbounded WebSocket fragment aggregation in http4s-blaze-server allows any client that completes a WebSocket handshake t
Heap exhaustion in the http4s Ember backend (0.23.x before 0.23.35 and 1.0.0 milestones before 1.0.0-M47) allows a singl
A crafted WebSocket frame can pin a worker thread and exhaust memory in the http4s Scala HTTP library, causing denial of
Heap-exhaustion denial of service in the http4s DigestAuth server middleware: an inverted stale-nonce comparison in Nonc
Http4s (http4s-blaze-server) is a minimal, idiomatic Scala interface for HTTP services. Rated high severity (CVSS 7.5),
http4s before versions 0.18.26, 0.20.20, and 0.21.2 has a local file inclusion vulnerability. Rated high severity (CVSS
Header injection in http4s blaze-server allows remote unauthenticated attackers to smuggle arbitrary HTTP headers - incl
Same weakness CWE-444 – HTTP Request/Response Smuggling
View allSame technique Authentication Bypass
View allShare
External POC / Exploit Code
Leaving vuln.today