Medium 6.3Published Sep 23, 2025

CVE-2025-59822Http4s vulnerable to HTTP Request Smuggling due to improper handling of HTTP trailer section

Updated under an hour ago (Oct 27, 2026, 12:10 PM ET)

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No exploitation reported and no EPSS estimate yet.

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Every CVE for http4s

Exploited in the last 30 days

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.

CVSS: 6.3 MEDIUM (v4.0, CNA)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
Weakness (CWE): CWE-444
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Sep 23, 2025
First seen by InfoSec Signals: Oct 19, 2026

Affected products

Affected products

http4s http4s http4s:http4s (from the name)	before 0.23.31; from 1.0.0-M1, < 1.0.0-M45	CNA record
typelevel http4s typelevel:http4s	before 0.23.31; 1.0.0; 1.0.0; 1.0.0; 1.0.0; 1.0.0; 1.0.0; 1.0.0; and 37 more ranges	NVD

References

References

https://github.com/http4s/http4s/security/advisories/GHSA-wcwh-7gfw-5wrr	x-refsource-confirm, exploit, vendor-advisory
https://github.com/http4s/http4s/commit/dd518f7c967e5165813b8d4a48a82b8fab852d41	x-refsource-misc, patch

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.