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HIGH

CVE-2017-7843

CVSS v3

7.5

HIGH

EPSS Score

2.9 %

exploit probability, as of 2026-10-19

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

  • CVE-2017-7843 Red Hat Product Security210 products fixed

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

  • RHSA-2017:3382 Red Hat Product Security64 products fixed

    Red Hat Security Advisory: firefox security update

Full record on NVD

Description

When Private Browsing mode is used, it is possible for a web worker to write persistent data to IndexedDB and fingerprint a user uniquely. IndexedDB should not be available in Private Browsing mode and this stored data will persist across multiple private browsing mode sessions because it is not cleared when exiting. This vulnerability affects Firefox ESR < 52.5.2 and Firefox < 57.0.1.

Technical details

Published
2018-06-11

Frequently asked questions

What is CVE-2017-7843?

When Private Browsing mode is used, it is possible for a web worker to write persistent data to IndexedDB and fingerprint a user uniquely. IndexedDB should not be available in Private Browsing mode and this stored data will persist across multiple private browsing mode sessions because it is not cleared when exiting. This vulnerability affects Firefox ESR < 52.5.2 and Firefox < 57.0.1.

Is CVE-2017-7843 actively exploited?

Active exploitation of CVE-2017-7843 has not been confirmed. Its EPSS score was 2.9% on 2026-10-19, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2017-7843?

CVE-2017-7843 has a CVSS v3 base score of 7.5 (HIGH severity).

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