# CVE-2026-73665: FreePBX UCP: Unauthenticated remote code execution via socket.io namespace auth bypass and AMI action injection

> Unauthenticated attackers can execute arbitrary commands on FreePBX UCP Node servers by bypassing Socket.IO authentication and injecting actions into the Asterisk Manager Interface.

- **Severity:** Critical 9.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 13 Aug 2026
- **Updated:** 18 Aug 2026
- **Also known as:** GHSA-37j8-fhxx-9vhp

## What is CVE-2026-73665?

CVE-2026-73665 is a critical command injection vulnerability in Sangoma Freepbx, published on 13 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

FreePBX is an open source IP PBX. Prior to 17.0.9, the UCP Node server on ports 8001 and 8003 uses io.use(checkAuth) in node/lib/server.js, but Socket.IO version 4 applies that middleware only to the default namespace. An unauthenticated client can connect to custom namespaces that do not consistently invoke checkAuth in node/lib/auth.js and send crafted event values containing carriage-return or newline characters through the Asterisk Manager Interface action path patched by node/lib/asterisk-manager-patch.js, allowing arbitrary commands to execute as the asterisk service user. This issue is fixed in version 17.0.9.

Weakness: CWE-862 (Missing Authorization)

## Which versions are affected by CVE-2026-73665?

It affects 1 product.


Products: Sangoma Freepbx.

## How do I fix CVE-2026-73665?

No fix has been published for CVE-2026-73665 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-73665 being exploited?

There is no known exploitation of CVE-2026-73665 in the wild and no public exploit code.

## Other vulnerabilities in Sangoma Freepbx

- [CVE-2025-57819](https://insights.sbomify.com/CVE-2025-57819/): Sangoma FreePBX Authentication Bypass (critical 10.0, exploited in the wild)
- [CVE-2019-19006](https://insights.sbomify.com/CVE-2019-19006/): Sangoma FreePBX Improper Authentication (critical 9.8, exploited in the wild)
- [CVE-2026-73663](https://insights.sbomify.com/CVE-2026-73663/): FreePBX: Unauthenticated SQL injection in FreePBX missedcall via inbound Caller ID name leads to administrator takeover (critical 9.3)
- [CVE-2026-46376](https://insights.sbomify.com/CVE-2026-46376/): FreePBX: Unauthenticated Use of Hard-Coded Credentials Vulnerability in FreePBX UCP Interface (critical 9.3)
- [CVE-2025-66039](https://insights.sbomify.com/CVE-2025-66039/): FreePBX Endpoint Manager Allows Unauthenticated Logins to Administrator Control Panel via Forged Basic Auth Header (critical 9.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-73665 and fix it if it is affected.

What it is: CVE-2026-73665 is a critical command injection vulnerability in Sangoma Freepbx, published on 13 Aug 2026. 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-2026-73665 in the wild and no public exploit code.

Affected product: Sangoma Freepbx. 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-2026-73665/ (Markdown: https://insights.sbomify.com/CVE-2026-73665/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-73665
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-73665
- OSV: https://osv.dev/vulnerability/CVE-2026-73665

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-73665/
Summaries are generated and may contain mistakes; the official description above is the record.