CVE-2026-22779 MEDIUM

CVE-2026-22779: BlackSheep ClientSession is vulnerable to CRLF injection

Vendor Neoteroi
Product BlackSheep
Weakness CWE-113 · HTTP response splitting
Published January 14, 2026
Last update January 14, 2026

CVSS base score

6.3/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

What the vulnerability does

01Description

BlackSheep is an asynchronous web framework to build event based web applications with Python. Prior to 2.4.6, the HTTP Client implementation in BlackSheep is vulnerable to CRLF injection. Missing headers validation makes it possible for an attacker to modify the HTTP requests (e.g. insert a new header) or even create a new HTTP request. Exploitation requires developers to pass unsanitized user input directly into headers.The server part is not affected because BlackSheep delegates to an underlying ASGI server handling of response headers. This vulnerability is fixed in 2.4.6.

Key dates

02Disclosure timeline

January 14, 2026 CVE published
January 14, 2026 Record updated