CVE-2021-21323 Information

Description

Brave is an open source web browser with a focus on privacy and security. In Brave versions 1.17.73-1.20.103 the CNAME adblocking feature added in Brave 1.17.73 accidentally initiated DNS requests that bypassed the Brave Tor proxy. Users with adblocking enabled would leak DNS requests from Tor windows to their DNS provider. (DNS requests that were not initiated by CNAME adblocking would go through Tor as expected.) This is fixed in Brave version 1.20.108

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Reference

https://github.com/brave/brave-browser/issues/13527 https://github.com/brave/brave-core/pull/7769 https://github.com/brave/brave-browser/security/advisories/GHSA-mqjf-9x5g-2rv6 https://github.com/brave/brave-core/commit/12fe321eaad8acc1cbd1d70b4128f687777bcf15 https://hackerone.com/reports/1077022

Attack Complexity

LOW

Privileges Required

NONE

User Interaction Required

NONE

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

LOW

Availability Impact

NONE

Base Score

NONE

Base Severity

5.3