Semaphore UI: Manager-to-owner privilege escalation via custom-role slug collision

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

8.8 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS

• CVE-2026-73293: 0.57% estimated exploitation activity in the next 30 days; percentile 47.17 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary Semaphore resolves a project member's effective permissions in ProjectMiddleware by looking up a role row whose slug matches the member's assigned role, and overwrites the built-in permission bitmask with that row's value. A member holding the built-in manager role creates a custom project role through POST /api/project/{id}/roles, a route gated only by the CanManageProjectResources permission that manager already holds. The role-creation validator does not reserve the built-in slug names (owner, manager, taskrunner, guest) and sets no ceiling on the permission bits a caller may grant. A manager creates a role with slug manager carrying the full bitmask 15, including the two owner-only bits CanUpdateProject and CanManageProjectUsers that manager does not hold. The slug lookup that backs permission resolution ignores project scope, so this attacker-created row is returned on the next request and the manager's effective permissions become owner-equivalent. Result: a project…

Published by the source

3 Sep 2026, 19:23 UTC

Last modified by the source

10 Sep 2026, 15:15 UTC

Source last checked

26 Oct 2026, 15:29 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-cxvf-gvfq-36w2

2. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GO-2026-6371

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-cxvf-gvfq-36w2

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# Patch Next advisory brief: CVE-2026-73293

Advisory: Semaphore UI: Manager-to-owner privilege escalation via custom-role slug collision
IDs: CVE-2026-73293, GHSA-cxvf-gvfq-36w2
Record: https://patchnext.com/advisories/cve-2026-73293 (revision 3, source checked 26 Oct 2026, 15:29 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/semaphoreui/semaphore 0.0.0-20260705182501-bb2a4e1f08c8. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/semaphoreui/semaphore: affected < 0.0.0-20260705182501-bb2a4e1f08c8; fixed in 0.0.0-20260705182501-bb2a4e1f08c8

## Suggested inspection (read-only)
- Go github.com/semaphoreui/semaphore: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/semaphoreui/semaphore.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-cxvf-gvfq-36w2 (OSV record GHSA-cxvf-gvfq-36w2 lists affected ranges: Go github.com/semaphoreui/semaphore >=0 <0.0.0-20260705182501-bb2a4e1f08c8 (fixed))
- Verified: https://osv.dev/vulnerability/GO-2026-6371 (OSV record GO-2026-6371 lists affected ranges: Go github.com/semaphoreui/semaphore >=0 <0.0.0-20260705182501-bb2a4e1f08c8 (fixed))
- Verified: https://github.com/advisories/GHSA-cxvf-gvfq-36w2 (GitHub-reviewed advisory GHSA-cxvf-gvfq-36w2 lists affected ranges: Go github.com/semaphoreui/semaphore >=0 <0.0.0-20260705182501-bb2a4e1f08c8)

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