Information disclosure in Brave

CVE-2021-21323

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

Vulnerability class: Information Disclosure

EPSS: 0.023 (81.2th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2021-21323?
CVE-2021-21323 is a medium-severity vulnerability in Brave, classified under Information Disclosure. CVSS score: 4.3/10. Published 2021-02-23.
How severe is CVE-2021-21323?
Medium severity. CVSS v3 base score is 4.3 out of 10.