VULNERABILITY INTELLIGENCE

CVE-2021-41084

CVSS score8.7 HIGH
EPSS probability1.23%
CISA KEVNot currently listed
Published2021-09-21
Last modified2026-06-17
CVSS vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N

Description

http4s is an open source scala interface for HTTP. In affected versions http4s is vulnerable to response-splitting or request-splitting attacks when untrusted user input is used to create any of the following fields: Header names (`Header.name`å), Header values (`Header.value`), Status reason phrases (`Status.reason`), URI paths (`Uri.Path`), URI authority registered names (`URI.RegName`) (through 0.21). This issue has been resolved in versions 0.21.30, 0.22.5, 0.23.4, and 1.0.0-M27 perform the following. As a matter of practice http4s services and client applications should sanitize any user input in the aforementioned fields before returning a request or response to the backend. The carriage return, newline, and null characters are the most threatening.

Weakness classification

  • security-advisories@github.com: CWE-918
  • nvd@nist.gov: CWE-74

Primary references