CVE-2025-59822

Http4s vulnerable to HTTP Request Smuggling due to improper handling of HTTP trailer section

Medium6.3EPSS 0.37%

Published: 23 Sept 2025
Updated: 23 Sept 2025
Reserved: 22 Sept 2025
Assigned by: GitHub_M

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.

Scores

CVSS scores of CVE-2025-59822, by who scored it
Scored by	CVSS	Score	Vector
GitHub_MCNA (assigner)	4.0	Medium6.3	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
NVDNVD · Analyzed	4.0	Medium6.3	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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS (exploitation in 30 days): 0.37% · top 68% of all CVEs (6 Nov 2026)
CISA SSVC: Exploitation: poc · Automatable: no · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.3.

Weakness

CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') (opens in a new tab)All about CWE-444 and its CVEs

Affected products

http4s · http4s
- affected < 0.23.31
- affected >= 1.0.0-M1, < 1.0.0-M45

Affected packages

From reviewed advisories of the GitHub Advisory Database.

Mavenorg.http4s:http4s-ember-core_2.12GHSA-wcwh-7gfw-5wrr (opens in a new tab)
Mavenorg.http4s:http4s-ember-core_2.13GHSA-wcwh-7gfw-5wrr (opens in a new tab)
Mavenorg.http4s:http4s-ember-core_3GHSA-wcwh-7gfw-5wrr (opens in a new tab)

References (2)

https://github.com/http4s/http4s/security/advisories/GHSA-wcwh-7gfw-5wrr (opens in a new tab)x_refsource_CONFIRMexploit
https://github.com/http4s/http4s/commit/dd518f7c967e5165813b8d4a48a82b8fab852d41 (opens in a new tab)x_refsource_MISC

Sources

The same CVE in the primary databases and aggregators, to check against.

Badge for a README or a ticket

[![CVE-2025-59822](https://trackcve.app/badge/CVE-2025-59822.svg)](https://trackcve.app/cve/CVE-2025-59822)

Record last updated 23 Sept 2025, 19:17 UTC.