CVE-2021-21323 - CVE House
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Status published Medium CVE-2021-21323

Regression in DNS leakage from Tor windows

Vulnerability 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

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

No credits recorded in the NVD database.

References

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Affected Vendor

Affected Software

brave-browser
Vulnerable Versions:
>= 1.17.73, < 1.20.108

Timeline

Official Publish: February 23rd, 2021
Last Modified: August 3rd, 2024
Added to House: July 21st, 2026

CVSS Vectors

V3: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

Weaknesses (CWE)

CWE-200

MITRE ATT&CK TTPs

T1213 Data from Information Repositories
Collection
T1005 Data from Local System
Collection
T1552 Unsecured Credentials
Credential Access
T1041 Exfiltration Over C2 Channel
Exfiltration