# CVE-2019-1957: Cisco IoT Field Network Director TLS Renegotiation Denial of Service Vulnerability

> Unauthenticated remote attackers can cause denial of service on Cisco IoT Field Network Director by flooding TLS renegotiation requests.

- **Severity:** Medium 5.3 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 8 Aug 2019
- **Updated:** 19 Nov 2024
- **Also known as:** GHSA-rmxg-r6q3-64j3

## What is CVE-2019-1957?

CVE-2019-1957 is a medium-severity denial of service vulnerability in Cisco IoT Field Network Director (IoT-FND), published on 8 Aug 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability in the web interface of Cisco IoT Field Network Director could allow an unauthenticated, remote attacker to trigger high CPU usage, resulting in a denial of service (DoS) condition on an affected device. The vulnerability is due to improper handling of Transport Layer Security (TLS) renegotiation requests. An attacker could exploit this vulnerability by sending renegotiation requests at a high rate. A successful exploit could increase the resource usage on the system, eventually leading to a DoS condition.

Weakness: CWE-399

## Which versions are affected by CVE-2019-1957?

It affects 1 product.


Products: Cisco Iot Field Network Director.

## How do I fix CVE-2019-1957?

No fix has been published for CVE-2019-1957 yet. Limit exposure of the affected software until one is available.

## Is CVE-2019-1957 being exploited?

There is no known exploitation of CVE-2019-1957 in the wild and no public exploit code.

## Other vulnerabilities in Cisco IoT Field Network Director (IoT-FND)

- [CVE-2020-3531](https://insights.sbomify.com/CVE-2020-3531/): Cisco IoT Field Network Director Unauthenticated REST API Vulnerability (critical 9.8)
- [CVE-2018-0270](https://insights.sbomify.com/CVE-2018-0270/): Cross-site request forgery in Cisco IoT Field Network Director (high 8.8)
- [CVE-2020-26072](https://insights.sbomify.com/CVE-2020-26072/): Cisco IoT Field Network Director SOAP API Authorization Bypass Vulnerability (high 8.7)
- [CVE-2026-20167](https://insights.sbomify.com/CVE-2026-20167/): Cisco IoT Field Network Director Remote Device Denial of Service Vulnerability (high 7.7)
- [CVE-2020-3392](https://insights.sbomify.com/CVE-2020-3392/): Cisco IoT Field Network Director Missing API Authentication Vulnerability (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-1957 and fix it if it is affected.

What it is: CVE-2019-1957 is a medium-severity denial of service vulnerability in Cisco IoT Field Network Director (IoT-FND), published on 8 Aug 2019. 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-2019-1957 in the wild and no public exploit code.

Affected product: Cisco IoT Field Network Director (IoT-FND). 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-2019-1957/ (Markdown: https://insights.sbomify.com/CVE-2019-1957/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-1957
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-1957
- OSV: https://osv.dev/vulnerability/CVE-2019-1957

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From sbomify Insights: https://insights.sbomify.com/CVE-2019-1957/
Summaries are generated and may contain mistakes; the official description above is the record.