VULNERABILITY INTELLIGENCE
CVE-2021-4138
CVSS score5.3 MEDIUM
EPSS probability0.85%
CISA KEVNot currently listed
Published2022-05-02
Last modified2026-06-17
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Description
Improved Host header checks to reject requests not sent to a well-known local hostname or IP, or the server-specified hostname.
Weakness classification
- nvd@nist.gov: NVD-CWE-noinfo
Primary references
- security@mozilla.org — Issue Tracking, Permissions Required, Third Party Advisory
- security@mozilla.org — Release Notes, Third Party Advisory
- af854a3a-2127-422b-91ae-364da2661108 — Issue Tracking, Permissions Required, Third Party Advisory
- af854a3a-2127-422b-91ae-364da2661108 — Release Notes, Third Party Advisory