CVE-2025-59822

MEDIUM
2025-09-23 [email protected]
6.3
CVSS 4.0
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CVSS 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/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
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
X

Lifecycle Timeline

4
Analysis Generated
Mar 28, 2026 - 19:13 vuln.today
Patch Released
Mar 28, 2026 - 19:13 nvd
Patch available
PoC Detected
Oct 08, 2025 - 17:35 vuln.today
Public exploit code
CVE Published
Sep 23, 2025 - 19:15 nvd
MEDIUM 6.3

Tags

Authentication Bypass Request Smuggling Http4S

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.

Analysis

Http4s is a Scala interface for HTTP services. Rated medium severity (CVSS 6.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.

Technical Context

This vulnerability is classified as HTTP Request/Response Smuggling (CWE-444), which allows attackers to manipulate HTTP request interpretation between frontend and backend servers. 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 products include: Typelevel Http4S. Version information: before 1.0.0.

Affected Products

Typelevel Http4S.

Remediation

A vendor patch is available. Apply the latest security update as soon as possible. Enforce strict HTTP parsing, normalize requests at proxy layer, use HTTP/2 end-to-end, reject ambiguous headers.

Priority Score

52
Low Medium High Critical
KEV: 0
EPSS: +0.1
CVSS: +32
POC: +20

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CVE-2025-59822 vulnerability details – vuln.today
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