Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, WebSocket FrameTranscoder.bodyLength rejects extended payload lengths above Integer.MAX_VALUE but permits negative 64-bit lengths. A remote client that completes a WebSocket handshake through an Ember server can send such a frame, causing the decoder to return an empty frame without advancing its input. The decode loop then runs indefinitely, pins a worker at full CPU, and grows an ArrayBuffer without bound, resulting in denial of service. This issue is fixed in versions 0.23.35 and 1.0.0-M47.
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Fixes
Solution
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Workaround
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References
History
Tue, 15 Sep 2026 22:30:00 +0000
| Type | Values Removed | Values Added |
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| First Time appeared |
Http4s
Http4s http4s |
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| Vendors & Products |
Http4s
Http4s http4s |
Tue, 15 Sep 2026 19:30:00 +0000
| Type | Values Removed | Values Added |
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| Description | Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, WebSocket FrameTranscoder.bodyLength rejects extended payload lengths above Integer.MAX_VALUE but permits negative 64-bit lengths. A remote client that completes a WebSocket handshake through an Ember server can send such a frame, causing the decoder to return an empty frame without advancing its input. The decode loop then runs indefinitely, pins a worker at full CPU, and grows an ArrayBuffer without bound, resulting in denial of service. This issue is fixed in versions 0.23.35 and 1.0.0-M47. | |
| Title | Http4s: WebSocket decoder accepts negative length, causing infinite decode loop | |
| Weaknesses | CWE-1284 CWE-835 |
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| References |
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| Metrics |
cvssV3_1
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Projects
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-09-15T19:19:04.868Z
Reserved: 2026-08-03T16:57:50.124Z
Link: CVE-2026-69210
No data.
Status : Received
Published: 2026-09-15T20:17:40.320
Modified: 2026-09-15T20:17:40.320
Link: CVE-2026-69210
No data.
OpenCVE Enrichment
Updated: 2026-09-15T22:15:16Z