# CVE-2026-79766: Termix: OS command injection in ACME/Let's Encrypt certificate-request handler via admin-controlled domain/email

> An authenticated administrator can inject shell commands via ACME settings, leading to arbitrary code execution on the server.

- **Severity:** Critical 9.1 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 24 Sep 2026
- **Updated:** 29 Sep 2026
- **Also known as:** GHSA-pr55-25gf-5f9v

## What is CVE-2026-79766?

CVE-2026-79766 is a critical command injection vulnerability in Termix-SSH Termix, published on 24 Sep 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

Termix is a web-based server management platform with SSH terminal, tunneling, and file editing capabilities. From 2.4.1 until 2.5.1, an authenticated Termix administrator can store attacker-controlled domain and email values through PATCH /users/acme-ssl-settings and trigger their interpolation into a certbot shell command through POST /users/acme-ssl-request. In src/backend/database/routes/acme-ssl-routes.ts, child_process.execSync invokes /bin/sh -c with those values only wrapped in double quotes, so shell metacharacters can execute arbitrary operating-system commands as the Termix backend process. Both HTTP webroot and DNS Cloudflare challenge modes are affected, and compromise exposes Termix databases, process secrets, stored credentials, and network reachability. This issue is fixed in version 2.5.1.

Weakness: CWE-78 (Improper Neutralization of Special Elements used in an OS Command)

## Which versions are affected by CVE-2026-79766?


## How do I fix CVE-2026-79766?

No fix has been published for CVE-2026-79766 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-79766 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-79766 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-79766 and fix it if it is affected.

What it is: CVE-2026-79766 is a critical command injection vulnerability in Termix-SSH Termix, published on 24 Sep 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-79766 exists.

Affected product: Termix-SSH Termix. 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-2026-79766/ (Markdown: https://insights.sbomify.com/CVE-2026-79766/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-79766
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-79766
- OSV: https://osv.dev/vulnerability/CVE-2026-79766

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-79766/
Summaries are generated and may contain mistakes; the official description above is the record.