# CVE-2021-33839: Information disclosure in n/a

> Attackers can confuse public and private QR codes to leak sensitive COVID-19 tracking data from the Luca Android application.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/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:** Not needed
- **Fix available:** No
- **Published:** 3 Jun 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-x4jr-cxw4-2x5h

## What is CVE-2021-33839?

CVE-2021-33839 is a high-severity vulnerability in n/a, published on 3 Jun 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Luca through 1.7.4 on Android allows remote attackers to obtain sensitive information about COVID-19 tracking because the QR code of a Public Location can be intentionally confused with the QR code of a Private Meeting.

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

## Which versions are affected by CVE-2021-33839?

It affects 1 product.


Products: Luca-App Luca.

## How do I fix CVE-2021-33839?

No fix has been published for CVE-2021-33839 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-33839 being exploited?

There is no known exploitation of CVE-2021-33839 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2021-33838](https://insights.sbomify.com/CVE-2021-33838/): Information disclosure in n/a (high 7.5)
- [CVE-2021-33840](https://insights.sbomify.com/CVE-2021-33840/): Business logic in n/a (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-33839 and fix it if it is affected.

What it is: CVE-2021-33839 is a high-severity vulnerability in n/a, published on 3 Jun 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-33839 in the wild and no public exploit code.

Affected product: n/a. 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-2021-33839/ (Markdown: https://insights.sbomify.com/CVE-2021-33839/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-33839
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-33839
- OSV: https://osv.dev/vulnerability/CVE-2021-33839

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-33839/
Summaries are generated and may contain mistakes; the official description above is the record.