CVE-2026-69205: high-severity vulnerability in http4s
Http4s: Ember Transfer-Encoding value parsing (TE.CL / TE.0 request smuggling)
Published
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21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.7epss 0.5%
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember’s HeaderP.parse uses a case-sensitive substring test for the Transfer-Encoding value and decodes header bytes with the platform default charset. Values such as Chunked are not recognized, values such as notchunked are incorrectly accepted, and Unicode case folding can turn a Kelvin-sign byte sequence into a match when UTF-8 is used. Intermediaries that apply RFC-compliant token and charset rules can therefore disagree with Ember’s Content-Length or zero-length framing, enabling TE.CL or TE.0 request smuggling, access-control bypass, cross-user request hijacking, and cache poisoning on the server path. Response smuggling through an ember-client gateway requires a malicious or compromised upstream. This issue is fixed in versions 0.23.35 and 1.0.0-M47.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
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%