CVE-2017-7843
Mozilla: Web worker in Private Browsing mode can write IndexedDB data
Severity
ImportantRed Hat Product Security
CVSS 3.0
Review impact separately from score.
Published · December 4, 2017
Updated · November 26, 2025
Description
A privacy flaw was discovered in Firefox. In Private Browsing mode, a web worker could write persistent data to IndexedDB, which was not cleared when exiting and would persist across multiple sessions. A malicious website could exploit the flaw to bypass private-browsing protections and uniquely fingerprint visitors.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
No mitigation is specified in collected source.
CVSS / CWE
CVSS 3.0 · 7.5CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CWE-212 · Improper Removal of Sensitive Information Before Storage or Transfer