# CVE-2021-22917: Information disclosure in https://github.com/brave/brave-core

> Brave Browser leaks DNS requests outside Tor when adblocking is enabled, exposing user browsing activity to network observers.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N`)
- **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 available:** No
- **Published:** 12 Jul 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-gvj3-42m2-8xqw

## What is CVE-2021-22917?

CVE-2021-22917 is a medium-severity vulnerability in https://github.com/brave/brave-core, published on 12 Jul 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 Browser Desktop between versions 1.17 and 1.20 is vulnerable to information disclosure by way of DNS requests in Tor windows not flowing through Tor if adblocking was enabled.

Weakness: CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor)

## Which versions are affected by CVE-2021-22917?

It affects 1 product.


Products: Brave Browser.

## How do I fix CVE-2021-22917?

No fix has been published for CVE-2021-22917 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-22917 being exploited?

There is no known exploitation of CVE-2021-22917 in the wild and no public exploit code.

## Other vulnerabilities in https://github.com/brave/brave-core

- [CVE-2023-52263](https://insights.sbomify.com/CVE-2023-52263/): Open redirect in n/a (medium 6.1)
- [CVE-2023-28364](https://insights.sbomify.com/CVE-2023-28364/): Open redirect in Brave Browser Android (medium 6.1)
- [CVE-2017-1000461](https://insights.sbomify.com/CVE-2017-1000461/): Security feature bypass in n/a (medium 4.7)
- [CVE-2016-9473](https://insights.sbomify.com/CVE-2016-9473/): Cross-site scripting in Brave Software Brave Browser iOS before 1.2.18 and Brave Browser Android 1.9.56 and earlier (medium 4.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-22917 and fix it if it is affected.

What it is: CVE-2021-22917 is a medium-severity vulnerability in https://github.com/brave/brave-core, published on 12 Jul 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-22917 in the wild and no public exploit code.

Affected product: https://github.com/brave/brave-core. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2021-22917/ (Markdown: https://insights.sbomify.com/CVE-2021-22917/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-22917
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-22917
- OSV: https://osv.dev/vulnerability/CVE-2021-22917

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-22917/
Summaries are generated and may contain mistakes; the official description above is the record.