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CVE-2017-5440

25
FAUCET Score

CVE-2017-5440 is a critical use-after-free vulnerability in Mozilla Firefox and Thunderbird, affecting versions prior to Firefox 53, Firefox ESR 52.1, and Thunderbird 52.1. This flaw, stemming from improper error handling during XSLT processing, allows attackers to trigger a crash and potentially execute arbitrary code. 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 severity, there is no evidence of active exploitation, publicly available exploit code, or significant community discussion surrounding this vulnerability.

Impacted Technologies

VendorProductVersion(s)CPE
8.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
6.0CPE matchmatch criteria
cpe:2.3:o:redhat:enterprise_linux:6.0:*:*:*:*:*:*:*
7.0CPE matchmatch criteria
cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
6.0CPE matchmatch criteria
cpe:2.3:o:redhat:enterprise_linux_desktop:6.0:*:*:*:*:*:*:*
7.0CPE matchmatch criteria
cpe:2.3:o:redhat:enterprise_linux_desktop:7.0:*:*:*:*:*:*:*

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
3.04%
Probability of exploitation in next 30 days
EPSS Percentile
86.1%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0304 is in the 77th percentile among its peer group of 36,862 CVEs.

Social Chatter

No social media mentions found for this CVE.

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 (7)

mozillapatch availablevia nvd_reference
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: firefox-0:52.1.0-2.el6_9
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: thunderbird-0:52.1.0-1.el6_9
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: firefox-0:52.1.0-2.el7_3
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: thunderbird-0:52.1.0-1.el7_3
View patch
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 5Fixed in: firefox
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 5Fixed in: thunderbird

Vendor Advisories (1)

redhatCVE-2017-5440Important

Mozilla: Use-after-free in txExecutionState destructor during XSLT processing (MFSA 2017-11, MFSA 2017-12)

Apr 19, 2017

References

access.redhat.com / errata/RHSA-2017:1104
Third Party Advisory
access.redhat.com / errata/RHSA-2017:1106
Third Party Advisory
access.redhat.com / errata/RHSA-2017:1201
Third Party Advisory
bugzilla.mozilla.org / show_bug.cgi
ExploitIssue TrackingPatchVendor Advisory
debian.org / security/2017/dsa-3831
Third Party Advisory
mozilla.org / security/advisories/mfsa2017-10
Vendor Advisory
mozilla.org / security/advisories/mfsa2017-11
Vendor Advisory
mozilla.org / security/advisories/mfsa2017-12
Vendor Advisory
mozilla.org / security/advisories/mfsa2017-13
Vendor Advisory
securityfocus.com / bid/97940
Third Party AdvisoryVDB Entry
securitytracker.com / id/1038320
Third Party AdvisoryVDB Entry