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CVE-2018-12395

25
FAUCET Score

CVE-2018-12395 describes a vulnerability in Firefox ESR versions prior to 60.3 and Firefox versions prior to 63, where a WebExtension could bypass domain restrictions using the webRequest API to rewrite Host headers, enabling domain fronting. This high-severity vulnerability (CVSS 7.5) allows an attacker to access restricted domains that share a host, with no user interaction required and high confidentiality impact. There is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
< 63.0CPE matchmatch criteria
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
< 60.3CPE matchmatch criteria
cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:*
8.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
9.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
14.04CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:*

CVSS Data

CVSS version used by this source: 3.0

7.5HIGH

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.0

Exploit Intelligence

EPSS Score
2.85%
Probability of exploitation in next 30 days
EPSS Percentile
85.2%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0285 is in the 74th percentile among its peer group of 51,551 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (3)

redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: firefox-0:60.3.0-1.el6
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: firefox-0:60.3.0-1.el7_5
View patch
mozillavendor investigatingvia nvd_reference
View patch

Vendor Advisories (1)

redhatCVE-2018-12395Moderate

Mozilla: WebExtension bypass of domain restrictions through header rewriting

Oct 23, 2018

References

access.redhat.com / errata/RHSA-2018:3005
Third Party Advisory
access.redhat.com / errata/RHSA-2018:3006
Third Party Advisory
bugzilla.mozilla.org / show_bug.cgi
Issue TrackingPermissions RequiredVendor Advisory
lists.debian.org / debian-lts-announce/2018/11/msg00008.html
Mailing ListThird Party Advisory
security.gentoo.org / glsa/201811-04
Third Party Advisory
usn.ubuntu.com / 3801-1
Third Party Advisory
debian.org / security/2018/dsa-4324
Third Party Advisory
mozilla.org / security/advisories/mfsa2018-26
Vendor Advisory
mozilla.org / security/advisories/mfsa2018-27
Vendor Advisory
securityfocus.com / bid/105718
Third Party AdvisoryVDB Entry
securitytracker.com / id/1041944
Third Party AdvisoryVDB Entry