Vulnerability in Neoteroi Blacksheep
CVE-2026-22779
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.
EPSS: 0.003 (23.0th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N.
Affected products
- Neoteroi Blacksheep — versions < 2.4.6
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Third Party Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC, Release Notes)
Frequently asked questions
- What is CVE-2026-22779?
- CVE-2026-22779 is a medium-severity vulnerability in Neoteroi Blacksheep, classified under HTTP Response Splitting. CVSS score: 5.3/10. Published 2026-01-14.
- How severe is CVE-2026-22779?
- Medium severity. CVSS v3 base score is 5.3 out of 10.