# CVE-2026-21639: Command injection in airFiber AF60

> A remote attacker in Wi-Fi range can execute arbitrary code on Ubiquiti airMAX and airFiber devices via a vulnerability in the wireless protocol.

- **Severity:** High 8.8 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 8 Jan 2026
- **Updated:** 30 Jul 2026
- **Also known as:** GHSA-9vw7-2gjw-jc6x

## What is CVE-2026-21639?

CVE-2026-21639 is a high-severity command injection vulnerability in Ubiquiti Inc airFiber AF60, published on 8 Jan 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A malicious actor in Wi-Fi range of the affected product could leverage a vulnerability in the airMAX Wireless Protocol to achieve a remote code execution (RCE) within the affected product.

Weakness: CWE-77 (Improper Neutralization of Special Elements used in a Command), CWE-120 (Buffer Copy without Checking Size of Input)

## Which versions are affected by CVE-2026-21639?

It affects 4 products.


Products: Ui Airfiber Af60-Xg Firmware, Ui Airfiber Af60 Firmware, Ui Airmax Ac Firmware, Ui Airmax M Firmware.

## How do I fix CVE-2026-21639?

No fix has been published for CVE-2026-21639 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-21639 being exploited?

There is no known exploitation of CVE-2026-21639 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-21639 and fix it if it is affected.

What it is: CVE-2026-21639 is a high-severity command injection vulnerability in Ubiquiti Inc airFiber AF60, published on 8 Jan 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-21639 in the wild and no public exploit code.

Affected product: Ubiquiti Inc airFiber AF60. 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-2026-21639/ (Markdown: https://insights.sbomify.com/CVE-2026-21639/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-21639
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-21639
- OSV: https://osv.dev/vulnerability/CVE-2026-21639

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-21639/
Summaries are generated and may contain mistakes; the official description above is the record.