CVE-2025-59822
September 23, 2025
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
https://github.com/http4s/http4s.git (GITHUB):
Affected version(s) >=v1.0.0-M1 <v1.0.0-M45Fix Suggestion:
Update to version v1.0.0-M45https://github.com/http4s/http4s.git (GITHUB):
Affected version(s) >=v0.1.0 <v0.23.31Fix Suggestion:
Update to version v0.23.31org.http4s:http4s-ember-core_2.13 (JAVA):
Affected version(s) >=0.10.0-M10 <0.23.31Fix Suggestion:
Update to version 0.23.31org.http4s:http4s-ember-core_3 (JAVA):
Affected version(s) >=1.0.0-M22 <1.0.0-M45Fix Suggestion:
Update to version 1.0.0-M45org.http4s:http4s-ember-core_2.12 (JAVA):
Affected version(s) >=0.10.0-M10 <0.23.31Fix Suggestion:
Update to version 0.23.31org.http4s:http4s-ember-core_2.13 (JAVA):
Affected version(s) >=1.0.0-M2 <1.0.0-M45Fix Suggestion:
Update to version 1.0.0-M45org.http4s:http4s-ember-core_3 (JAVA):
Affected version(s) >=0.22.0-M8 <0.23.31Fix Suggestion:
Update to version 0.23.31Related Resources (4)
Do you need more information?
Contact UsCVSS v4
Base Score:
6.3
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
PRESENT
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
LOW
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
7.5
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
NONE
Weakness Type (CWE)
Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
EPSS
Base Score:
0.07
