Vulnerability · Published Sep 23, 2025 · Assigned by GitHub_M
CVE-2025-59822Http4s vulnerable to HTTP Request Smuggling due to improper handling of HTTP trailer section
Medium 6.3
In plain English
A medium-severity security flaw in http4s from http4s. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 32% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Http4s is a Scala interface for HTTP services. In versions from 1.0.0-M1 to before 1.0.0-M45 and before 0.23.31, http4s is vulnerable to HTTP Request Smuggling due to improper handling of HTTP trailer section. This vulnerability could enable attackers to bypass front-end servers security controls, launch targeted attacks against active users, and poison web caches. A pre-requisite for exploitation involves the web application being deployed behind a reverse-proxy that forwards trailer headers. This issue has been patched in versions 1.0.0-M45 and 0.23.31.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Maven | org.http4s:http4s-ember-core_2.12 | 0.23.31 | GHSA-wcwh-7gfw-5wrr |
| Maven | org.http4s:http4s-ember-core_2.13 | 0.23.31 | GHSA-wcwh-7gfw-5wrr |
| Maven | org.http4s:http4s-ember-core_2.13 | 1.0.0-M45 | GHSA-wcwh-7gfw-5wrr |
| Maven | org.http4s:http4s-ember-core_3 | 0.23.31 | GHSA-wcwh-7gfw-5wrr |
| Maven | org.http4s:http4s-ember-core_3 | 1.0.0-M45 | GHSA-wcwh-7gfw-5wrr |
Affected products (as reported)
Weakness: CWE-444 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N