SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2021-4138

Improved Host header checks to reject requests not sent to a well-known local hostname or IP, or the server-specified hostname.

MEDIUM 5.3EPSS 0.83%

Does this matter?

Lower severity and a low EPSS score (0.83%). Track it; it rarely justifies an emergency change on its own.

Description

Improved Host header checks to reject requests not sent to a well-known local hostname or IP, or the server-specified hostname.

CVSS 3.1
5.3 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
EPSS
0.83% probability · 56th percentile
CISA KEV
Not listed
Affected
mozilla/geckodriver
Source
security@mozilla.org

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.