In Brave Desktop 1.17 through 1.33 before 1.33.106, when CNAME-based adblocking and a proxying extension with a SOCKS fallback are enabled,…

published 2021-12-27 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-32600

cvss: 7.5; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 3.1%; EPSS 3.1% chance of exploitation in 30 days, percentile 88%
public exploits: 0; none known

In Brave Desktop 1.17 through 1.33 before 1.33.106, when CNAME-based adblocking and a proxying extension with a SOCKS fallback are enabled, additional DNS requests are issued outside of the proxying extension using the system's DNS settings, resulting in information disclosure. NOTE: this issue exists because of an incomplete fix for CVE-2021-21323 and CVE-2021-22916.

Patch / fix

links 2

github.com/brave/brave-core#10742 pull request
github.com/brave/brave-browser/issues/19070 advisory

Exploit prediction

3.15% chance of exploitation in the next 30 days, higher than 88% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/brave/brave-browser/issues/19070 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
NVD	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD	2.0	4.3	AV:N/AC:M/Au:N/C:P/I:N/A:N

Classification

Weakness

CWE-200 Exposure of Sensitive Information to an Unauthorized Actor

References

github.com /brave/brave-core/pull/10742
patch, third-party-advisory
github.com /brave/brave-browser/issues/19070
exploit, issue-tracking, patch, third-party-advisory
github.com /brave/brave-browser/issues/20079
issue-tracking, release-notes, third-party-advisory
hackerone.com /reports/1377864
permissions-required

Sources

CVE List CVE-2021-45884
NVD CVE-2021-45884

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary