{"id":"CVE-2026-69209","state":"PUBLISHED","title":"Http4s: WebSocket decoder accepts unbounded message sizes","description":"Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, The shared WebSocket decoder permits unbounded message buffering because defragmentation accumulates fragments without a limit and FrameTranscoder accepts declared lengths up to Int.MaxValue. A remote client that completes a WebSocket handshake against an http4s-blaze-server or http4s-ember-server endpoint can exhaust server memory with oversized frames or fragmented messages. The patched decoder applies a configurable 64 MiB default limit to individual frames and defragmented messages through EmberServerBuilder.withMaxWebSocketMessageSize. This issue is fixed in versions 0.23.35 and 1.0.0-M47.","publishedAt":"2026-09-15T18:55:29.782Z","updatedAt":"2026-09-16T18:37:15.546Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","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-jrxx-w2m8-5hf5","https://github.com/http4s/http4s/commit/d578c3c9da6193627d40fa785e612cda7fcd77b3","https://github.com/http4s/http4s/releases/tag/v0.23.35","https://github.com/http4s/http4s/releases/tag/v1.0.0-M47"],"weaknesses":["CWE-400","CWE-770"],"ingestedAt":"2026-10-29T20:12:49.727Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/69xxx/CVE-2026-69209.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-69209","state":"PUBLISHED","datePublished":"2026-09-15T18:55:29.782Z","dateUpdated":"2026-09-16T18:37:15.546Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-08-03T16:57:50.124Z"},"containers":{"cna":{"title":"Http4s: WebSocket decoder accepts unbounded message sizes","descriptions":[{"lang":"en","value":"Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, The shared WebSocket decoder permits unbounded message buffering because defragmentation accumulates fragments without a limit and FrameTranscoder accepts declared lengths up to Int.MaxValue. A remote client that completes a WebSocket handshake against an http4s-blaze-server or http4s-ember-server endpoint can exhaust server memory with oversized frames or fragmented messages. The patched decoder applies a configurable 64 MiB default limit to individual frames and defragmented messages through EmberServerBuilder.withMaxWebSocketMessageSize. 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-jrxx-w2m8-5hf5","name":"https://github.com/http4s/http4s/security/advisories/GHSA-jrxx-w2m8-5hf5","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/http4s/http4s/commit/d578c3c9da6193627d40fa785e612cda7fcd77b3","name":"https://github.com/http4s/http4s/commit/d578c3c9da6193627d40fa785e612cda7fcd77b3","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":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-400","lang":"en","description":"CWE-400: Uncontrolled Resource Consumption","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-770","lang":"en","description":"CWE-770: Allocation of Resources Without Limits or Throttling","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-09-15T18:55:29.782Z"},"source":{"advisory":"GHSA-jrxx-w2m8-5hf5","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-16T18:25:00.686488Z","id":"CVE-2026-69209","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-16T18:37:15.546Z"}}]}}}