CVE-2026-69210: high-severity vulnerability in http4s
Http4s: WebSocket decoder accepts negative length, causing infinite decode loop
Published · Updated
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21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.5epss 0.6%
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products
http4s · http4sRelated CVEs — http4s
In the same product, most dangerous first.
CVE-2020-5280HIGHLocal file inclusion vulnerability in http4sEPSS 7.0%CVE-2021-21294HIGHUnbounded connection acceptance in http4s-blaze-serverEPSS 2.2%CVE-2021-32643MEDIUMStaticFile.fromUrl can leak presence of a directoryEPSS 1.4%CVE-2021-41084HIGHResponse Splitting from unsanitized headers in http4sEPSS 1.2%CVE-2023-22465HIGHHttp4s has fatal error parsing User-Agent and Server headersEPSS 0.9%CVE-2026-69208HIGHHttp4s: DigestAuth nonce map grows unboundedEPSS 0.8%