# CVE-2022-40735: Denial of service in n/a

> Attackers can cause server-side resource exhaustion and denial of service by exploiting inefficient Diffie-Hellman key agreement calculations.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 14 Nov 2022
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-8vmc-7qrc-q5mx, UBUNTU-CVE-2022-40735, USN-6854-1

## What is CVE-2022-40735?

CVE-2022-40735 is a high-severity denial of service vulnerability in n/a, published on 14 Nov 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The Diffie-Hellman Key Agreement Protocol allows use of long exponents that arguably make certain calculations unnecessarily expensive, because the 1996 van Oorschot and Wiener paper found that "(appropriately) short exponents" can be used when there are adequate subgroup constraints, and these short exponents can lead to less expensive calculations than for long exponents. This issue is different from CVE-2002-20001 because it is based on an observation about exponent size, rather than an observation about numbers that are not public keys. The specific situations in which calculation expense would constitute a server-side vulnerability depend on the protocol (e.g., TLS, SSH, or IKE) and the DHE implementation details. In general, there might be an availability concern because of server-side resource consumption from DHE modular-exponentiation calculations. Finally, it is possible for an attacker to exploit this vulnerability and CVE-2002-20001 together.

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2022-40735?

It affects 1 product.


Products: Diffie-Hellman Key Exchange Project Diffie-Hellman Key Exchange.

## How do I fix CVE-2022-40735?

Apply the vendor's patch.

## Is CVE-2022-40735 being exploited?

There is no known exploitation of CVE-2022-40735 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2022-40735 and fix it if it is affected.

What it is: CVE-2022-40735 is a high-severity denial of service vulnerability in n/a, published on 14 Nov 2022. 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-2022-40735 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-2022-40735/ (Markdown: https://insights.sbomify.com/CVE-2022-40735/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-40735
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-40735
- OSV: https://osv.dev/vulnerability/CVE-2022-40735

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-40735/
Summaries are generated and may contain mistakes; the official description above is the record.