# CVE-2020-6829: Information disclosure in Firefox

> An attacker with electromagnetic trace access can recover private keys from Firefox EC signatures due to nonce leakage in the wNAF algorithm.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/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:** Yes
- **Published:** 28 Oct 2020
- **Updated:** 4 Aug 2024
- **Also known as:** ALPINE-CVE-2020-6829, DEBIAN-CVE-2020-6829, GHSA-cc99-55qg-f87r, UBUNTU-CVE-2020-6829

## What is CVE-2020-6829?

CVE-2020-6829 is a medium-severity vulnerability in Mozilla Firefox, published on 28 Oct 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

When performing EC scalar point multiplication, the wNAF point multiplication algorithm was used; which leaked partial information about the nonce used during signature generation. Given an electro-magnetic trace of a few signature generations, the private key could have been computed. This vulnerability affects Firefox < 80 and Firefox for Android < 80.

## Which versions are affected by CVE-2020-6829?

It affects 2 products.


Products: Mozilla Firefox, Mozilla Firefox Mobile.

## How do I fix CVE-2020-6829?

Upgrade to a fixed version.

## Is CVE-2020-6829 being exploited?

There is no known exploitation of CVE-2020-6829 in the wild and no public exploit code.

## Other vulnerabilities in Mozilla Firefox

- [CVE-2019-11708](https://insights.sbomify.com/CVE-2019-11708/): Mozilla Firefox and Thunderbird Sandbox Escape (critical 10.0, exploited in the wild)
- [CVE-2010-3765](https://insights.sbomify.com/CVE-2010-3765/): Mozilla Multiple Products Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2022-26486](https://insights.sbomify.com/CVE-2022-26486/): Mozilla Firefox Use-After-Free (critical 9.6, exploited in the wild)
- [CVE-2022-26485](https://insights.sbomify.com/CVE-2022-26485/): Mozilla Firefox Use-After-Free (high 8.8, exploited in the wild)
- [CVE-2019-11707](https://insights.sbomify.com/CVE-2019-11707/): Mozilla Firefox and Thunderbird Type Confusion (high 8.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-6829 and fix it if it is affected.

What it is: CVE-2020-6829 is a medium-severity vulnerability in Mozilla Firefox, published on 28 Oct 2020. 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-2020-6829 in the wild and no public exploit code.

Affected product: Mozilla Firefox. 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-2020-6829/ (Markdown: https://insights.sbomify.com/CVE-2020-6829/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-6829
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-6829
- OSV: https://osv.dev/vulnerability/CVE-2020-6829

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-6829/
Summaries are generated and may contain mistakes; the official description above is the record.