# CVE-2020-35857: Stack consumption in trust-dns-server

> Attackers can cause stack consumption and denial of service by sending DNS MX or SRV records with null targets to applications using the trust-dns-server crate.

- **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:** 31 Dec 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-4cww-f7w5-x525, RUSTSEC-2020-0001

## What is CVE-2020-35857?

CVE-2020-35857 is a high-severity denial of service vulnerability in n/a, published on 31 Dec 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An issue was discovered in the trust-dns-server crate before 0.18.1 for Rust. DNS MX and SRV null targets are mishandled, causing stack consumption.

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2020-35857?

3 open source packages ship an affected version, including trust-dns-server. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `trust-dns-server` | crates.io | From 0.16.0 | 0.18.1 |
| `trust-dns-server` | crates.io | From 0.16.0 | 0.18.1 |
| `trust-dns-server` | crates.io | From 0.16.0 | 0.18.1 |

Products: Trust-Dns-Server Project Trust-Dns-Server.

## How do I fix CVE-2020-35857?

Upgrade trust-dns-server to 0.18.1 or later.

## Is CVE-2020-35857 being exploited?

There is no known exploitation of CVE-2020-35857 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-35857 and fix it if it is affected.

What it is: CVE-2020-35857 is a high-severity denial of service vulnerability in n/a, published on 31 Dec 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-2020-35857 in the wild and no public exploit code.

Affected packages and fixed versions:
- trust-dns-server (crates.io): affected from 0.16.0; fixed in 0.18.1
- trust-dns-server (crates.io): affected from 0.16.0; fixed in 0.18.1
- trust-dns-server (crates.io): affected from 0.16.0; fixed in 0.18.1

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-2020-35857/ (Markdown: https://insights.sbomify.com/CVE-2020-35857/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-35857
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-35857
- OSV: https://osv.dev/vulnerability/CVE-2020-35857

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-35857/
Summaries are generated and may contain mistakes; the official description above is the record.