CVE-2021-21323 : Brave is an open source web browser with a focus on privacy and security. In Bra

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

Published 2021-02-23 23:15:13

Updated 2021-03-01 16:14:07

Source GitHub, Inc.

View at NVD, CVE.org

Vulnerability category: Information leak

Products affected by CVE-2021-21323

Brave » Brave
Versions from including (>=) 1.17.73 and up to, including, (<=) 1.20.103
cpe:2.3:a:brave:brave:*:*:*:*:*:*:*:*
Matching versions

Exploit prediction scoring system (EPSS) score for CVE-2021-21323

EPSS FAQ

0.49%

Probability of exploitation activity in the next 30 days EPSS Score History

~ 63 %

Percentile, the proportion of vulnerabilities that are scored at or less

CVSS scores for CVE-2021-21323

Base Score	Base Severity	CVSS Vector	Exploitability Score	Impact Score	Score Source
4.3	MEDIUM	AV:N/AC:M/Au:N/C:P/I:N/A:N	8.6	2.9	NIST
Access Vector: Network Access Complexity: Medium Authentication: None Confidentiality Impact: Partial Integrity Impact: None Availability Impact: None
5.3	MEDIUM	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N	3.9	1.4	NIST
Attack Vector: Network Attack Complexity: Low Privileges Required: None User Interaction: None Scope: Unchanged Confidentiality: Low Integrity: None Availability: None
4.3	MEDIUM	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N	2.8	1.4	GitHub, Inc.
Attack Vector: Network Attack Complexity: Low Privileges Required: None User Interaction: Required Scope: Unchanged Confidentiality: Low Integrity: None Availability: None

CWE ids for CVE-2021-21323

CWE-200 Exposure of Sensitive Information to an Unauthorized Actor

The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.

Assigned by: security-advisories@github.com (Primary)

References for CVE-2021-21323

https://github.com/brave/brave-browser/security/advisories/GHSA-mqjf-9x5g-2rv6

Regression in DNS leakage from Tor windows · Advisory · brave/brave-browser · GitHub
Third Party Advisory
https://hackerone.com/reports/1077022

Sign in
Permissions Required;Third Party Advisory

CVEs referencing this url
https://github.com/brave/brave-browser/issues/13527

[hackerone] Tor DNS issue · Issue #13527 · brave/brave-browser · GitHub
Patch;Third Party Advisory
https://github.com/brave/brave-core/commit/12fe321eaad8acc1cbd1d70b4128f687777bcf15

Merge pull request #7769 from brave/tor-dns-leak · brave/brave-core@12fe321 · GitHub
Patch;Third Party Advisory
https://github.com/brave/brave-core/pull/7769

Fix Tor dns leak by darkdh · Pull Request #7769 · brave/brave-core · GitHub
Patch;Third Party Advisory

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Vulnerability Details : CVE-2021-21323

Products affected by CVE-2021-21323

Exploit prediction scoring system (EPSS) score for CVE-2021-21323

CVSS scores for CVE-2021-21323

CWE ids for CVE-2021-21323

References for CVE-2021-21323