Vulnerability-Lookup

CVE-2026-47724 (GCVE-0-2026-47724)

Vulnerability from cvelistv5 – Published: 2026-07-23 20:20 – Updated: 2026-07-23 20:20

Title

nebula-mesh: API endpoints lack ownership checks, enabling cross-operator privilege escalation

Summary

nebula-mesh is a self-hosted control plane for Slack Nebula mesh virtual private network. Prior to version 0.3.4, the `/api/v1/*` route surface trusts the bearer token alone for authorisation on most endpoints. The codebase itself admits this at `internal/api/hosts.go:384`: "API trusts the bearer token for authorisation; per-CA ownership is enforced only in the Web layer." The Web UI gates state-changing routes through `loadAccessibleCA` (`internal/web/cas.go`); CA-management endpoints in `internal/api/cas.go` ALSO have proper `canAccessCA` gates. The gap is on the host, network, firewall, mobile-bundle, and most operator endpoints. Combined with the per-operator CA model from ADR 0002, this gives any non-admin operator API key broad cross-tenant access — instant privilege escalation in the worst case. Version 0.3.4 fixes the issue.

Severity

9.9 (Critical)


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

CWE

CWE-862 - Missing Authorization

Assigner

GitHub_M

References

2 references

URL	Tags
https://github.com/forgekeep/nebula-mesh/security…	x_refsource_CONFIRM
https://github.com/forgekeep/nebula-mesh/commit/9…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
juev	nebula-mesh	Affected: < 0.3.4

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "nebula-mesh",
          "vendor": "juev",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.3.4"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "nebula-mesh is a self-hosted control plane for Slack Nebula mesh virtual private network. Prior to version 0.3.4, the `/api/v1/*` route surface trusts the bearer token alone for authorisation on most endpoints. The codebase itself admits this at `internal/api/hosts.go:384`: \"API trusts the bearer token for authorisation; per-CA ownership is enforced only in the Web layer.\" The Web UI gates state-changing routes through `loadAccessibleCA` (`internal/web/cas.go`); CA-management endpoints in `internal/api/cas.go` ALSO have proper `canAccessCA` gates. The gap is on the host, network, firewall, mobile-bundle, and most operator endpoints. Combined with the per-operator CA model from ADR 0002, this gives any non-admin operator API key broad cross-tenant access \u2014 instant privilege escalation in the worst case. Version 0.3.4 fixes the issue."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 9.9,
            "baseSeverity": "CRITICAL",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "LOW",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-862",
              "description": "CWE-862: Missing Authorization",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-23T20:20:59.494Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/forgekeep/nebula-mesh/security/advisories/GHSA-598g-h2vc-h5vg",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/forgekeep/nebula-mesh/security/advisories/GHSA-598g-h2vc-h5vg"
        },
        {
          "name": "https://github.com/forgekeep/nebula-mesh/commit/9d8bcd7667ecd0c2975cc71fb35a02fe131f76f2",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/forgekeep/nebula-mesh/commit/9d8bcd7667ecd0c2975cc71fb35a02fe131f76f2"
        }
      ],
      "source": {
        "advisory": "GHSA-598g-h2vc-h5vg",
        "discovery": "UNKNOWN"
      },
      "title": "nebula-mesh: API endpoints lack ownership checks, enabling cross-operator privilege escalation"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-47724",
    "datePublished": "2026-07-23T20:20:59.494Z",
    "dateReserved": "2026-05-19T21:29:25.482Z",
    "dateUpdated": "2026-07-23T20:20:59.494Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-47724",
      "date": "2026-07-26",
      "epss": "0.0035",
      "percentile": "0.27595"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-47724\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-07-23T21:17:04.477\",\"lastModified\":\"2026-07-23T21:17:04.477\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"nebula-mesh is a self-hosted control plane for Slack Nebula mesh virtual private network. Prior to version 0.3.4, the `/api/v1/*` route surface trusts the bearer token alone for authorisation on most endpoints. The codebase itself admits this at `internal/api/hosts.go:384`: \\\"API trusts the bearer token for authorisation; per-CA ownership is enforced only in the Web layer.\\\" The Web UI gates state-changing routes through `loadAccessibleCA` (`internal/web/cas.go`); CA-management endpoints in `internal/api/cas.go` ALSO have proper `canAccessCA` gates. The gap is on the host, network, firewall, mobile-bundle, and most operator endpoints. Combined with the per-operator CA model from ADR 0002, this gives any non-admin operator API key broad cross-tenant access \u2014 instant privilege escalation in the worst case. Version 0.3.4 fixes the issue.\"}],\"affected\":[{\"source\":\"security-advisories@github.com\",\"affectedData\":[{\"vendor\":\"juev\",\"product\":\"nebula-mesh\",\"versions\":[{\"version\":\"\u003c 0.3.4\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H\",\"baseScore\":9.9,\"baseSeverity\":\"CRITICAL\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"CHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.1,\"impactScore\":6.0}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-862\"}]}],\"references\":[{\"url\":\"https://github.com/forgekeep/nebula-mesh/commit/9d8bcd7667ecd0c2975cc71fb35a02fe131f76f2\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/forgekeep/nebula-mesh/security/advisories/GHSA-598g-h2vc-h5vg\",\"source\":\"security-advisories@github.com\"}]}}"
  }
}

GHSA-598G-H2VC-H5VG

Vulnerability from github – Published: 2026-06-08 23:09 – Updated: 2026-06-08 23:09

Summary

nebula-mesh: API endpoints lack ownership checks, enabling cross-operator privilege escalation

Details

The /api/v1/* route surface trusts the bearer token alone for authorisation on most endpoints. The codebase itself admits this at internal/api/hosts.go:384: "API trusts the bearer token for authorisation; per-CA ownership is enforced only in the Web layer."

The Web UI gates state-changing routes through loadAccessibleCA (internal/web/cas.go); CA-management endpoints in internal/api/cas.go ALSO have proper canAccessCA gates. The gap is on the host, network, firewall, mobile-bundle, and most operator endpoints. Combined with the per-operator CA model from ADR 0002, this gives any non-admin operator API key broad cross-tenant access — instant privilege escalation in the worst case.

Affected

All released versions prior to v0.3.4.

Exploit chain

A) Mint admin API key from any operator key (instant privilege escalation)

internal/api/operators.go:118 — handleCreateOperatorAPIKey does no admin check and no actor/target-operator ownership check. Any operator key can call it for any operator (including admins) and receive a fresh bearer.

curl -X POST -H "Authorization: Bearer <low-priv-key>" \
  https://server/api/v1/operators/<admin-id>/api-keys \
  -H 'Content-Type: application/json' -d '{"name":"oops"}'
# Returns: {"key":"<32-byte admin bearer>","entry":{...}}

Reuse the returned key for subsequent requests → full admin.

B) Cross-operator host takeover via reenroll

internal/api/hosts.go:321,330 → mintEnrollmentTokenForHost. Looks up host by URL param, mints a single-use enrollment token, returns it. No ownership check.

curl -X POST -H "Authorization: Bearer <low-priv-key>" \
  https://server/api/v1/hosts/<victim-host-id>/reenroll
# Returns: {"enrollment_token":"<uuid>",...}

Caller POSTs /api/v1/enroll with their own X25519 + Ed25519 keypairs. enroll.go:175 overwrites signing_pub_pem; SaveCertificateAndEnrollHost overwrites the cert. Legitimate agent's next signed poll fails bad_signature. Attacker now owns the victim's Nebula identity.

C) Cross-tenant CRUD on hosts, networks, firewall

The same gap applies across: - /api/v1/hosts* — create, list, get, update, delete, block, unblock - /api/v1/networks* — create, list, get - /api/v1/networks/{id}/firewall — get, PUT - /api/v1/hosts/{id}/mobile-bundle (already filed as public issue #119)

All trust bearer-auth alone. Any operator can read or mutate any other operator's resources.

Affected operator-management handlers (in addition to A)

Beyond handleCreateOperatorAPIKey (covered by A), internal/api/operators.go is missing admin gates on: - handleListOperators (line 66) — operator roster info disclosure - handleDisableOperator (line 79) — DoS / sabotage - handleEnableOperator (line 94) — re-enable disabled operators - handleRevokeOperatorAPIKey (line 157) — invalidate any operator's API keys - handleListOperatorAPIKeys (line 173) — API-key metadata disclosure

handleCreateOperator (line 26) IS properly gated (actorIsAdmin at line 27).

NOT affected (verified)

internal/api/cas.go properly gates every CA endpoint via canAccessCA (calls at lines 70, 176, 216) and admin shortcuts at lines 39, 82. An earlier description draft mistakenly listed /api/v1/cas/{id}/rotate as affected — that endpoint is properly protected. CAs are not in this gap.

Impact

Any non-admin operator → admin via one curl (A).
Any non-admin operator → ownership of any victim's hosts with cert + identity transfer (B).
Mass cross-tenant CRUD including firewall-rule mutation (C).
Any operator → disable/enable other operators, revoke their API keys, enumerate the operator roster.

CVSS 3.1: AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H — 9.6.

Suggested fix

Shared helpers in a new internal/api/authz.go, mirroring the Web layer's loadAccessibleCA:

func (s *Server) requireAdmin(w http.ResponseWriter, r *http.Request) bool
func (s *Server) requireOperatorAccess(w http.ResponseWriter, r *http.Request, operatorID string) bool
func (s *Server) requireHostAccess(w http.ResponseWriter, r *http.Request, hostID string) (*models.Host, bool)
func (s *Server) requireNetworkAccess(w http.ResponseWriter, r *http.Request, networkID string) (*models.Network, bool)

Each loads the resource, resolves its CA via *.CAID, accepts if actorIsAdmin(ctx) OR actor owns the CA. Reject 403 forbidden; audit-log api.<resource>.forbidden with the reason.

The operator-management endpoints take requireAdmin instead (operator ownership doesn't map to CA ownership).

Apply at the top of every host-, network-, firewall-, mobile-bundle-touching API handler, plus the 5 operator endpoints listed above. The legacy config-key path retains admin (preserves backward compatibility); the broader legacy-fallback question is tracked separately as issue #121.

Test matrix

admin → all operations permitted
owning non-admin → operations on owned hosts/networks permitted
non-owner non-admin → 403 + audit entry
legacy config-key → preserved (admin)
unauthenticated → existing 401 from middleware

Coordinated context

Subsumes public issue #119 (mobile-bundle authz). Issue #121 (actor.go:40 legacy-admin fallback) is a separate concern tracked independently.