# CVE-2016-8635: Weak cryptography in nss

> An attacker can recover private keys by exploiting a small subgroup confinement flaw in the Diffie Hellman key exchange of the NSS library.

- **Severity:** Medium 5.3 (`CVSS:3.0/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:** 1 Aug 2018
- **Updated:** 6 Aug 2024
- **Also known as:** DEBIAN-CVE-2016-8635, GHSA-j6rc-c6gr-mf89, UBUNTU-CVE-2016-8635

## What is CVE-2016-8635?

CVE-2016-8635 is a medium-severity vulnerability in Mozilla Network Security Services, published on 1 Aug 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

It was found that Diffie Hellman Client key exchange handling in NSS 3.21.x was vulnerable to small subgroup confinement attack. An attacker could use this flaw to recover private keys by confining the client DH key to small subgroup of the desired group.

Weakness: CWE-320, CWE-358 (Improperly Implemented Security Check for Standard)

## Which versions are affected by CVE-2016-8635?

It affects 7 products.


Products: Mozilla Network Security Services, Redhat Enterprise Linux Desktop, Redhat Enterprise Linux Server, Redhat Enterprise Linux Server Aus, Redhat Enterprise Linux Server Eus, Redhat Enterprise Linux Server Tus, Redhat Enterprise Linux Workstation.

## How do I fix CVE-2016-8635?

Upgrade to a fixed version.

## Is CVE-2016-8635 being exploited?

There is no known exploitation of CVE-2016-8635 in the wild and no public exploit code.

## Other vulnerabilities in Mozilla Network Security Services

- [CVE-2019-17006](https://insights.sbomify.com/CVE-2019-17006/): Memory corruption in NSS (critical 9.8)
- [CVE-2017-5461](https://insights.sbomify.com/CVE-2017-5461/): Memory corruption in Firefox (critical 9.8)
- [CVE-2009-2404](https://insights.sbomify.com/CVE-2009-2404/): Memory corruption in n/a (critical 9.3)
- [CVE-2017-11695](https://insights.sbomify.com/CVE-2017-11695/): Memory corruption in n/a (high 7.8)
- [CVE-2017-11696](https://insights.sbomify.com/CVE-2017-11696/): Memory corruption in n/a (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2016-8635 and fix it if it is affected.

What it is: CVE-2016-8635 is a medium-severity vulnerability in Mozilla Network Security Services, published on 1 Aug 2018. 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-2016-8635 in the wild and no public exploit code.

Affected product: Mozilla Network Security Services. 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-2016-8635/ (Markdown: https://insights.sbomify.com/CVE-2016-8635/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2016-8635
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2016-8635
- OSV: https://osv.dev/vulnerability/CVE-2016-8635

---
From sbomify Insights: https://insights.sbomify.com/CVE-2016-8635/
Summaries are generated and may contain mistakes; the official description above is the record.