HTTP Response Splitting Affecting blacksheep package, versions [2.3.1a1, 2.4.6)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-PYTHON-BLACKSHEEP-14943967
- published15 Jan 2026
- disclosed14 Jan 2026
- creditJinho Ju
Introduced: 14 Jan 2026
CVE-2026-22779 (opens in a new tab)How to fix?
Upgrade blacksheep to version 2.4.6 or higher.
Overview
blacksheep is a Fast web framework for Python asyncio
Affected versions of this package are vulnerable to HTTP Response Splitting via the Client implementation. An attacker can manipulate HTTP requests or inject additional headers by supplying specially input containing carriage return and line feed characters in HTTP client headers.