# CVE-2021-1276: Cisco Data Center Network Manager Certificate Validation Vulnerabilities

> Attackers can perform man-in-the-middle attacks to extract sensitive information or alter API requests due to insufficient certificate validation.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 20 Jan 2021
- **Updated:** 12 Nov 2024
- **Also known as:** GHSA-w5fp-2j8v-x63m

## What is CVE-2021-1276?

CVE-2021-1276 is a high-severity vulnerability in Cisco Data Center Network Manager, published on 20 Jan 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Multiple vulnerabilities in Cisco Data Center Network Manager (DCNM) could allow an attacker to spoof a trusted host or construct a man-in-the-middle attack to extract sensitive information or alter certain API requests. These vulnerabilities are due to insufficient certificate validation when establishing HTTPS requests with the affected device. For more information about these vulnerabilities, see the Details section of this advisory.

Weakness: CWE-295 (Improper Certificate Validation)

## Which versions are affected by CVE-2021-1276?

It affects 1 product.


Products: Cisco Data Center Network Manager.

## How do I fix CVE-2021-1276?

No fix has been published for CVE-2021-1276 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-1276 being exploited?

There is no known exploitation of CVE-2021-1276 in the wild and no public exploit code.

## Other vulnerabilities in Cisco Data Center Network Manager

- [CVE-2020-3382](https://insights.sbomify.com/CVE-2020-3382/): Cisco Data Center Network Manager Authentication Bypass Vulnerability (critical 9.8)
- [CVE-2019-15975](https://insights.sbomify.com/CVE-2019-15975/): Cisco Data Center Network Manager Authentication Bypass Vulnerabilities (critical 9.8)
- [CVE-2019-15976](https://insights.sbomify.com/CVE-2019-15976/): Cisco Data Center Network Manager Authentication Bypass Vulnerabilities (critical 9.8)
- [CVE-2019-15977](https://insights.sbomify.com/CVE-2019-15977/): Cisco Data Center Network Manager Authentication Bypass Vulnerabilities (critical 9.8)
- [CVE-2019-1619](https://insights.sbomify.com/CVE-2019-1619/): Cisco Data Center Network Manager Authentication Bypass Vulnerability (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-1276 and fix it if it is affected.

What it is: CVE-2021-1276 is a high-severity vulnerability in Cisco Data Center Network Manager, published on 20 Jan 2021. 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-2021-1276 in the wild and no public exploit code.

Affected product: Cisco Data Center Network Manager. 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-2021-1276/ (Markdown: https://insights.sbomify.com/CVE-2021-1276/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-1276
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-1276
- OSV: https://osv.dev/vulnerability/CVE-2021-1276

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-1276/
Summaries are generated and may contain mistakes; the official description above is the record.