# CVE-2026-20321: Cisco Application Policy Infrastructure Controller API Command Injection Vulnerability

> Authenticated attackers with admin credentials can execute arbitrary root commands on Cisco APIC via the web management API due to insufficient input validation.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 7 Oct 2026
- **Updated:** 8 Oct 2026
- **Also known as:** GHSA-r72r-fhv8-5qgq

## What is CVE-2026-20321?

CVE-2026-20321 is a medium-severity command injection vulnerability in Cisco Application Policy Infrastructure Controller (APIC), published on 7 Oct 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

A vulnerability in the web-based management API for Cisco Application Policy Infrastructure Controller (APIC) could allow an authenticated, remote attacker to execute arbitrary commands as the root user. To exploit this vulnerability, the attacker must have valid administrative credentials.

This vulnerability is due to insufficient input validation of user-controlled command arguments. An attacker could exploit this vulnerability by authenticating using the API and sending crafted input. A successful exploit could allow the attacker to execute arbitrary commands on the underlying operating system of an affected device with root-level privileges.

Weakness: CWE-544 (Missing Standardized Error Handling Mechanism)

## Which versions are affected by CVE-2026-20321?


## How do I fix CVE-2026-20321?

No fix has been published for CVE-2026-20321 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-20321 being exploited?

There is no known exploitation of CVE-2026-20321 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-20321 and fix it if it is affected.

What it is: CVE-2026-20321 is a medium-severity command injection vulnerability in Cisco Application Policy Infrastructure Controller (APIC), published on 7 Oct 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-20321 in the wild and no public exploit code.

Affected product: Cisco Application Policy Infrastructure Controller (APIC). 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-2026-20321/ (Markdown: https://insights.sbomify.com/CVE-2026-20321/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-20321
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-20321
- OSV: https://osv.dev/vulnerability/CVE-2026-20321

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-20321/
Summaries are generated and may contain mistakes; the official description above is the record.