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CVE-2026-73293 high CVSS 8.8

Privilege Escalation in github.com/semaphoreui/semaphore (CVE-2026-73293)

Summary

Vulnerability in github.com/semaphoreui/semaphore (CVE-2026-73293). Successful exploitation can lead to full system takeover. Exploitable via POST /api/project/{id}/roles. Mitigation: upgrade to 0.0.0-20260705182501-bb2a4e1f08c8 or later.

Original description

The description as published by the source.

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, task_runner, 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 manager escalates to full owner of the project with one authenticated request, then adds or removes members, changes project settings, deletes the project, or demotes the legitimate owner.

Affected

semaphoreui/semaphore v2.18.12 (current latest as of 2026-06-09) and develop HEAD. Confirmed live-exploitable on v2.18.12 (commit 8a4dcf0); the affected files are unchanged on develop with no fix commit since the tag. Earlier releases that ship PRO custom project…

Source: NIST National Vulnerability Database NVD GitHub Advisory

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2026-73293 has been found in github.com/semaphoreui/semaphore.
Attackers can target a specific entry point like POST /api/project/{id}/roles over the network to misuse the product.
Successful exploitation can lead to full system takeover. CVSS score: 8.8/10.
What to do: upgrade github.com/semaphoreui/semaphore to 0.0.0-20260705182501-bb2a4e1f08c8 or later.
If unsure, ask your IT team or search "github.com/semaphoreui/semaphore CVE-2026-73293" on the vendor's site.

CVE-2026-73293 (github.com/semaphoreui/semaphore) — CWE-269 / CVSS v3 8.8
Attack vector: remote (network-reachable) / no user interaction
Attack surface: POST /api/project/{id}/roles / GET /api/project/42/role / PUT /api/project/42 / POST /api/project/42/roles
Patched: 0.0.0-20260705182501-bb2a4e1f08c8 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (CWE-269) exists in github.com/semaphoreui/semaphore. Attackers reach the vulnerable code path via POST /api/project/{id}/roles.

📍 Affected scope

Check the vendor advisory for the affected versions of github.com/semaphoreui/semaphore. Attack surface: POST /api/project/{id}/roles / GET /api/project/42/role / PUT /api/project/42 / POST /api/project/42/roles.

🔥 Severity

Severity: High (CVSS 8.8/10). Successful exploitation can lead to full system takeover.

🔧 How to fix

Update to 0.0.0-20260705182501-bb2a4e1f08c8.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual POST /api/project/{id}/roles requests with malformed payloads or SQL meta-characters. Run grep -r 'github.com/semaphoreui/semaphore' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify 
    grep -r 'github.com/semaphoreui/semaphore' . | grep -v node_modules

    リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で github.com/semaphoreui/semaphore を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Hunt for indicators of compromise detect 
    grep 'POST /api/project/{id}/roles' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'

    アクセスログで POST /api/project/{id}/roles への異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。

  3. 3
    Apply patch patch 
    Upgrade github.com/semaphoreui/semaphore to 0.0.0-20260705182501-bb2a4e1f08c8

    ステージング環境で 0.0.0-20260705182501-bb2a4e1f08c8 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスと、Step 2 で見つけた異常検知の続報チェックを含めること。

  4. 4
    Post-deployment verification verify 
    Replay attack against POST /api/project/{id}/roles on staging to confirm patch closes the vector

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番では Step 2 と同じログクエリでアラート再発が無いか継続監視。

Affected packages

go github.com/semaphoreui/semaphore
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.0.0-20260705182501-bb2a4e1f08c8"}]}]

References

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