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CVE-2017-7843

26
FAUCET Score

CVE-2017-7843 describes a vulnerability in Firefox ESR < 52.5.2 and Firefox < 57.0.1 where web workers could write persistent data to IndexedDB even in Private Browsing mode, allowing for unique user fingerprinting across sessions. This high-severity vulnerability (CVSS 7.5) has a low attack complexity and could lead to high confidentiality impacts, as user data persists despite private browsing expectations. While there is no evidence of active exploitation or public exploit code (Metasploit, Nuclei, ExploitDB), the vulnerability has garnered some community discussion.

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:*:*:*:*:*:*:*
< 57.0.1CPE matchmatch criteria
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
< 52.5.2CPE matchmatch criteria
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*

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
2.99%
Probability of exploitation in next 30 days
EPSS Percentile
85.9%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0299 is in the 75th percentile among its peer group of 51,506 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-0:52.5.1-1.el6_9
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: firefox-0:52.5.1-1.el7_4
View patch
mozillavendor investigatingvia nvd_reference
View patch

Vendor Advisories (1)

redhatCVE-2017-7843Important

Mozilla: Web worker in Private Browsing mode can write IndexedDB data

Dec 4, 2017

References

access.redhat.com / errata/RHSA-2017:3382
Third Party Advisory
bugzilla.mozilla.org / show_bug.cgi
ExploitIssue TrackingThird Party Advisory
lists.debian.org / debian-lts-announce/2017/12/msg00003.html
Third Party Advisory
debian.org / security/2017/dsa-4062
Third Party Advisory
mozilla.org / security/advisories/mfsa2017-27
Vendor Advisory
mozilla.org / security/advisories/mfsa2017-28
Vendor Advisory
securityfocus.com / bid/102039
Issue TrackingThird Party AdvisoryVDB Entry
securityfocus.com / bid/102112
Third Party AdvisoryVDB Entry
securitytracker.com / id/1039954
Third Party AdvisoryVDB Entry