Predictive Vulnerability Intelligence.

Product

  • Product
  • Pricing
  • Documentation

Company

  • About
  • Partnerships
  • Blog
  • Support

Legal

  • Terms
  • Privacy
  • Data Licensing

© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2018-5178

25
FAUCET Score

CVE-2018-5178 describes a buffer overflow vulnerability in Mozilla Firefox and Thunderbird (including ESR versions) that occurs during UTF8 to Unicode string conversion when processing extremely large data within JavaScript. This flaw requires a malicious or vulnerable legacy extension to be present for exploitation. Rated 8.1 HIGH on CVSS, it poses a significant risk with potential for high impact on confidentiality, integrity, and availability, despite requiring high attack complexity. There is no public exploit code, evidence of active exploitation, or significant community discussion surrounding this vulnerability.

Impacted Technologies

VendorProductVersion(s)CPE
7.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:7.0:*:*:*:*:*:*:*
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:*:*:*:*:*:*:*
< 52.8.0CPE matchmatch criteria
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
< 52.8.0CPE matchmatch criteria
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.0

8.1HIGH

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

Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
2.2
Impact Score
5.9
CvssVersion
3.0

Exploit Intelligence

EPSS Score
5.06%
Probability of exploitation in next 30 days
EPSS Percentile
91.4%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0506 is in the 59th percentile among its peer group of 8,918 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.2 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 (5)

redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: firefox-0:52.8.0-1.el6_9
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: thunderbird-0:52.8.0-2.el6_9
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: firefox-0:52.8.0-1.el7_5
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: thunderbird-0:52.8.0-1.el7_5
View patch
mozillavendor investigatingvia nvd_reference
View patch

Vendor Advisories (1)

redhatCVE-2018-5178Moderate

Mozilla: Buffer overflow during UTF-8 to Unicode string conversion through legacy extension

May 9, 2018

References

access.redhat.com / errata/RHSA-2018:1414
Third Party Advisory
access.redhat.com / errata/RHSA-2018:1415
Third Party Advisory
access.redhat.com / errata/RHSA-2018:1725
Third Party Advisory
access.redhat.com / errata/RHSA-2018:1726
Third Party Advisory
bugzilla.mozilla.org / show_bug.cgi
Issue TrackingPermissions RequiredVendor Advisory
lists.debian.org / debian-lts-announce/2018/05/msg00007.html
Mailing ListThird Party Advisory
lists.debian.org / debian-lts-announce/2018/05/msg00013.html
Mailing ListThird Party Advisory
security.gentoo.org / glsa/201810-01
Third Party Advisory
security.gentoo.org / glsa/201811-13
Third Party Advisory
usn.ubuntu.com / 3660-1
Third Party Advisory
debian.org / security/2018/dsa-4199
Third Party Advisory
debian.org / security/2018/dsa-4209
Third Party Advisory
mozilla.org / security/advisories/mfsa2018-12
Vendor Advisory
mozilla.org / security/advisories/mfsa2018-13
Vendor Advisory
securityfocus.com / bid/104138
Third Party AdvisoryVDB Entry
securitytracker.com / id/1040898
Third Party AdvisoryVDB Entry