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CVE-2026-69210

Http4s: WebSocket decoder accepts negative length, causing infinite decode loop PUBLISHED

Description (CNA)

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.

Affected (CNA)

Vendor / productVersions
http4s / http4saffected < 0.23.35; affected >= 1.0.0-M1, < 1.0.0-M47

CWE

CWE-835, CWE-1284

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.