CVE-2021-21323 Regression in DNS leakage from Tor windows
Brave browser users with adblocking enabled leak DNS requests from Tor windows, exposing browsing activity to DNS providers.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2021-21323?
CVE-2021-21323 is a medium-severity vulnerability in brave-browser, published on 23 Feb 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
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
Weakness: CWE-200
Which versions are affected by CVE-2021-21323?
It affects 1 product.
Products include Brave Brave.
How do I fix CVE-2021-21323?
No fix has been published for CVE-2021-21323 yet. Limit exposure of the affected software until one is available.
Is CVE-2021-21323 being exploited?
There is no known exploitation of CVE-2021-21323 in the wild and no public exploit code.
Other vulnerabilities in brave-browser
Sources
Also known as GHSA-mqjf-9x5g-2rv6.