CVE-2021-21323

mediumpriority · track · 22EPSS 0.023 · 83 %ileEUUS
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
2.26% (83rd) EPSS
CVSS 4.3 · medium
Is it mine?
2 products
Check your exposure
Who says so?
3 sources
cnnvd · enisa_euvd · nvd

EPSS · scored 2026-10-29

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

01

cvss

Technical severity, 0–10. One row per scoring source.

5.3
010

base score 0–10 · higher = more severe · hover a vector to decode

v2.04.3mediumAV:N/AC:M/Au:N/C:P/I:N/A:Nprimary · NVD / NIST USexploitability 8.6 · impact 2.9
v3.15.3mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:Nprimary · NVD / NIST USexploitability 3.9 · impact 1.4
v3.14.3mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:Nsecondary · ENISA EU
v3.14.3mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:Nsecondary · security-advisories@github.comexploitability 2.8 · impact 1.4
v3.14.9mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N/E:Usecondary · CVSS-BT (t0sche)
02

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-200US
03

affected products (2)

Products and version ranges known to be affected.

04

also known as (2)

Other names and identifiers for this entity.

05

sources

Which sources assert this record, and when.

cnnvdenisa_euvdnvdNVDCVE.orgMITRE
published 2021-02-23modified 2026-06-17
06

references (16)

External citations — patches, advisories, analysis.

scry

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