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Fencer Intel
high 7.5

CVE-2021-45884 json

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 4y ago modified 4mo ago also EUVD-2021-32600

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
3.2%
EPSS 3.2% chance of exploitation in 30 days, percentile 88%
public exploits
0
none known

Summary

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

Is CVE-2021-45884 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Exploit prediction

3.15% chance of exploitation in the next 30 days, higher than 88% of all scored CVEs (FIRST EPSS, 2026-11-09).

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

Sources

Fencer Intel 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.