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CVE-2016-5254

30
FAUCET Score

CVE-2016-5254 is a critical use-after-free vulnerability in the nsXULPopupManager::KeyDown function of Mozilla Firefox before version 48.0 and Firefox ESR 45.x before 45.3. This flaw allows remote attackers to execute arbitrary code or cause a denial of service through heap memory corruption and application crashes by manipulating the Alt key during top-level menu item selection. With a CVSS score of 9.8 (CRITICAL), it presents a severe risk due to its network-based attack vector, low attack complexity, and high impact on confidentiality, integrity, and availability. Despite its high severity, there is no evidence of active exploitation, no public exploit code available (Metasploit, Nuclei, ExploitDB), and minimal community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
<= 47.0.1CPE matchmatch criteria
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
45.1.0CPE matchmatch criteria
cpe:2.3:a:mozilla:firefox:45.1.0:*:*:*:*:*:*:*
45.1.1CPE matchmatch criteria
cpe:2.3:a:mozilla:firefox:45.1.1:*:*:*:*:*:*:*
45.2.0CPE matchmatch criteria
cpe:2.3:a:mozilla:firefox:45.2.0:*:*:*:*:*:*:*
45.3.0CPE matchmatch criteria
cpe:2.3:a:mozilla:firefox:45.3.0:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.0

9.8CRITICAL

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.9
CvssVersion
3.0

Exploit Intelligence

EPSS Score
2.95%
Probability of exploitation in next 30 days
EPSS Percentile
85.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0295 is in the 77th percentile among its peer group of 36,862 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (4)

redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 5Fixed in: firefox-0:45.3.0-1.el5_11
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: firefox-0:45.3.0-1.el6_8
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: firefox-0:45.3.0-1.el7_2
View patch
mozillavendor investigatingvia nvd_reference
View patch

Vendor Advisories (1)

redhatCVE-2016-5254Low

Mozilla: Use-after-free when using alt key and toplevel menus (MFSA 2016-70)

Aug 2, 2016

References

lists.opensuse.org / opensuse-security-announce/2016-08/msg00004.html
lists.opensuse.org / opensuse-security-announce/2016-08/msg00029.html
rhn.redhat.com / errata/RHSA-2016-1551.html
bugzilla.mozilla.org / show_bug.cgi
Issue TrackingPermissions Required
security.gentoo.org / glsa/201701-15
debian.org / security/2016/dsa-3640
mozilla.org / security/announce/2016/mfsa2016-70.html
Vendor Advisory
oracle.com / technetwork/topics/security/linuxbulletinjul2016-3090544.html
Third Party Advisory
securityfocus.com / bid/92261
securitytracker.com / id/1036508
ubuntu.com / usn/USN-3044-1