CVE-2026-69216
mediumHttp4s is a Scala interface for HTTP services.
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember’s chunk decoder trims the chunk-size token and accepts leading plus or minus signs instead of requiring one or more hexadecimal digits followed by the required CRLF. When an intermediary forwards chunked data without re-encoding and interprets malformed chunk boundaries differently, an unauthenticated attacker can create TE.TE request smuggling that bypasses intermediary controls, poisons caches, or hijacks the request queue. The same response-path leniency can enable response smuggling against an ember-client used as a gateway when the upstream is malicious or compromised. 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:L/I:L/A:N Affected products
Not reported by the source (unknown — not "none").
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
No vendor advisory or patch reference tagged by NVD. Check the references below.
References
- https://github.com/http4s/http4s/commit/d78612a5abd5a2547487598d3342be05573e16f0 security-advisories@github.com
- https://github.com/http4s/http4s/releases/tag/v0.23.35 security-advisories@github.com
- https://github.com/http4s/http4s/releases/tag/v1.0.0-M47 security-advisories@github.com
- https://github.com/http4s/http4s/security/advisories/GHSA-jrpm-956j-96jg security-advisories@github.com