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CVE-2016-5276

31
FAUCET Score

CVE-2016-5276 is a critical use-after-free vulnerability in the mozilla::a11y::DocAccessible::ProcessInvalidationList function, affecting Mozilla Firefox before 49.0, Firefox ESR 45.x before 45.4, and Thunderbird before 45.4. This flaw, triggered by a crafted aria-owns attribute, allows remote attackers to execute arbitrary code or cause a denial of service through heap memory corruption. With a CVSS score of 9.8 (CRITICAL), it presents a severe risk due to its network-based attack vector and low attack complexity, potentially leading to complete compromise of confidentiality, integrity, and availability. Despite its high severity, there is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
<= 48.0.2CPE 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
4.01%
Probability of exploitation in next 30 days
EPSS Percentile
89.5%
Percentile rank of EPSS score among Peer Group
As of 2026-07-26
Model: v2026.06.15
This CVE's current EPSS score of 0.0401 is in the 83rd percentile among its peer group of 36,835 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-0:45.4.0-1.el5_11
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: firefox-0:45.4.0-1.el6_8
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: firefox-0:45.4.0-1.el7_2
View patch
mozillavendor investigatingvia nvd_reference
View patch

Vendor Advisories (1)

redhatCVE-2016-5276Important

Mozilla: Heap-use-after-free in mozilla::a11y::DocAccessible::ProcessInvalidationList (MFSA 2016-85, MFSA 2016-86)

Sep 20, 2016

References

rhn.redhat.com / errata/RHSA-2016-1912.html
bugzilla.mozilla.org / show_bug.cgi
Issue Tracking
security.gentoo.org / glsa/201701-15
mozilla.org / security/advisories/mfsa2016-86
mozilla.org / security/advisories/mfsa2016-88
debian.org / security/2016/dsa-3674
mozilla.org / security/announce/2016/mfsa2016-85.html
Vendor Advisory
oracle.com / technetwork/topics/security/linuxbulletinoct2016-3090545.html
securityfocus.com / bid/93049
securitytracker.com / id/1036852