{"id":"CVE-2026-69204","state":"PUBLISHED","title":"Http4s: Ember accepts Transfer-Encoding combined with Content-Length (CL.TE request smuggling)","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.","publishedAt":"2026-09-15T18:43:14.850Z","updatedAt":"2026-09-15T19:00:49.739Z","severity":{"score":9.2,"label":"Critical","version":"4.0","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","source":"GitHub_M"},"assigner":"GitHub_M","products":["http4s http4s"],"affected":[{"vendor":"http4s","product":"http4s","versions":[{"version":"< 0.23.35","status":"affected"},{"version":">= 1.0.0-M1, < 1.0.0-M47","status":"affected"}]}],"references":["https://github.com/http4s/http4s/security/advisories/GHSA-8h4c-x2wg-6xp8","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"],"weaknesses":["CWE-444"],"ingestedAt":"2026-10-29T20:12:49.727Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/69xxx/CVE-2026-69204.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-69204","state":"PUBLISHED","datePublished":"2026-09-15T18:43:14.850Z","dateUpdated":"2026-09-15T19:00:49.739Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-08-03T16:57:50.124Z"},"containers":{"cna":{"title":"Http4s: Ember accepts Transfer-Encoding combined with Content-Length (CL.TE request smuggling)","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"http4s","product":"http4s","versions":[{"version":"< 0.23.35","status":"affected"},{"version":">= 1.0.0-M1, < 1.0.0-M47","status":"affected"}]}],"references":[{"url":"https://github.com/http4s/http4s/security/advisories/GHSA-8h4c-x2wg-6xp8","name":"https://github.com/http4s/http4s/security/advisories/GHSA-8h4c-x2wg-6xp8","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/http4s/http4s/commit/9feaf8677951a52af906ae9664ff6f0543d9d810","name":"https://github.com/http4s/http4s/commit/9feaf8677951a52af906ae9664ff6f0543d9d810","tags":["x_refsource_MISC"]},{"url":"https://github.com/http4s/http4s/releases/tag/v0.23.35","name":"https://github.com/http4s/http4s/releases/tag/v0.23.35","tags":["x_refsource_MISC"]},{"url":"https://github.com/http4s/http4s/releases/tag/v1.0.0-M47","name":"https://github.com/http4s/http4s/releases/tag/v1.0.0-M47","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"HIGH","vulnAvailabilityImpact":"LOW","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":9.2,"baseSeverity":"CRITICAL","vectorString":"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","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-444","lang":"en","description":"CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-09-15T18:43:14.850Z"},"source":{"advisory":"GHSA-8h4c-x2wg-6xp8","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-15T19:00:36.832324Z","id":"CVE-2026-69204","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-15T19:00:49.739Z"}}]}}}