# CVE-2017-2909: Denial of service in Mongoose

> A specially crafted DNS request triggers an infinite loop in the Cesanta Mongoose library, causing high CPU usage and denial of service.

- **Severity:** High 7.5 (`CVSS:3.0/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:** 7 Nov 2017
- **Updated:** 17 Sep 2024
- **Also known as:** DEBIAN-CVE-2017-2909, GHSA-r2hq-55rv-r3g7

## What is CVE-2017-2909?

CVE-2017-2909 is a high-severity denial of service vulnerability in Cesanta Mongoose, published on 7 Nov 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An infinite loop programming error exists in the DNS server functionality of Cesanta Mongoose 6.8 library. A specially crafted DNS request can cause an infinite loop resulting in high CPU usage and Denial Of Service. An attacker can send a packet over the network to trigger this vulnerability.

Weakness: CWE-835 (Loop with Unreachable Exit Condition)

## Which versions are affected by CVE-2017-2909?

It affects 1 product.


Products: Cesanta Mongoose.

## How do I fix CVE-2017-2909?

Upgrade to a fixed version.

## Is CVE-2017-2909 being exploited?

There is no known exploitation of CVE-2017-2909 in the wild and no public exploit code.

## Other vulnerabilities in Cesanta Mongoose

- [CVE-2022-25299](https://insights.sbomify.com/CVE-2022-25299/): Arbitrary File Write (critical 9.8)
- [CVE-2020-25756](https://insights.sbomify.com/CVE-2020-25756/): Memory corruption in n/a (critical 9.8)
- [CVE-2019-19307](https://insights.sbomify.com/CVE-2019-19307/): Integer overflow in n/a (critical 9.8)
- [CVE-2019-12951](https://insights.sbomify.com/CVE-2019-12951/): Memory corruption in n/a (critical 9.8)
- [CVE-2018-20353](https://insights.sbomify.com/CVE-2018-20353/): Use after free in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-2909 and fix it if it is affected.

What it is: CVE-2017-2909 is a high-severity denial of service vulnerability in Cesanta Mongoose, published on 7 Nov 2017. 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-2017-2909 in the wild and no public exploit code.

Affected product: Cesanta Mongoose. 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-2017-2909/ (Markdown: https://insights.sbomify.com/CVE-2017-2909/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-2909
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-2909
- OSV: https://osv.dev/vulnerability/CVE-2017-2909

---
From sbomify Insights: https://insights.sbomify.com/CVE-2017-2909/
Summaries are generated and may contain mistakes; the official description above is the record.