SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2018-12395

By rewriting the Host: request headers using the webRequest API, a WebExtension can bypass domain restrictions through domain fronting.

HIGH 7.5EPSS 2.85%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (2.85%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

By rewriting the Host: request headers using the webRequest API, a WebExtension can bypass domain restrictions through domain fronting. This would allow access to domains that share a host that are otherwise restricted. This vulnerability affects Firefox ESR < 60.3 and Firefox < 63.

CVSS 3.0
7.5 HIGHCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS
2.85% probability · 86th percentile
CISA KEV
Not listed
Affected
mozilla/firefox · mozilla/firefox esr · debian/debian linux · canonical/ubuntu linux · redhat/enterprise linux desktop · redhat/enterprise linux server · redhat/enterprise linux server eus · redhat/enterprise linux workstation
Source
security@mozilla.org

References

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