{"cve":"CVE-2026-69204","nvd":{"published":"2026-09-15T19:17:37.580","modified":"2026-09-16T20:39:16.610","status":"Deferred","description":"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.","cvss_v4":{"vector":"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","score":9.2},"cvss_v3":null,"cwes":["CWE-444"],"references":["https://github.com/http4s/http4s/commit/9feaf8677951a52af906ae9664ff6f0543d9d810","https://github.com/http4s/http4s/releases/tag/v0.23.35","https://github.com/http4s/http4s/releases/tag/v1.0.0-M47","https://github.com/http4s/http4s/security/advisories/GHSA-8h4c-x2wg-6xp8"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:54:41.405518556+00:00"},"epss":{"cve":"CVE-2026-69204","score":0.00574,"percentile":0.47436,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-8h4c-x2wg-6xp8","url":"https://osv.dev/vulnerability/GHSA-8h4c-x2wg-6xp8","summary":"Http4s Ember accepts Transfer-Encoding combined with Content-Length (CL.TE request smuggling)","modified":"2026-09-15T20:00:39.617163532Z","packages":[{"ecosystem":"Maven","name":"org.http4s:http4s-ember-core_2.12","purl":"pkg:maven/org.http4s/http4s-ember-core_2.12","ranges":["<0.23.35"],"fixed":["0.23.35"]},{"ecosystem":"Maven","name":"org.http4s:http4s-ember-core_2.13","purl":"pkg:maven/org.http4s/http4s-ember-core_2.13","ranges":["<0.23.35"],"fixed":["0.23.35"]},{"ecosystem":"Maven","name":"org.http4s:http4s-ember-core_3","purl":"pkg:maven/org.http4s/http4s-ember-core_3","ranges":["<0.23.35"],"fixed":["0.23.35"]},{"ecosystem":"Maven","name":"org.http4s:http4s-ember-core_2.13","purl":"pkg:maven/org.http4s/http4s-ember-core_2.13","ranges":[">=1.0.0-M1 <1.0.0-M47"],"fixed":["1.0.0-M47"]},{"ecosystem":"Maven","name":"org.http4s:http4s-ember-core_3","purl":"pkg:maven/org.http4s/http4s-ember-core_3","ranges":[">=1.0.0-M1 <1.0.0-M47"],"fixed":["1.0.0-M47"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}