Vulnerability-Lookup

GHSA-G4X6-JCVR-9M3G

Vulnerability from github – Published: 2026-07-14 20:26 – Updated: 2026-07-14 20:26

Summary

nebula-mesh: Web UI host creation ignores configured enrollment token TTL and mints 24-hour bearer enrollment tokens

Details

Summary

The nebula-mgmt Web UI host-creation path ignores both the server-wide enrollment_token_ttl security setting and per-network network_config.enrollment_token_ttl overrides. API host creation and token-regeneration paths use the configured TTL resolver, but POST /ui/hosts hardcodes now.Add(24 * time.Hour) for newly minted agent enrollment tokens. In deployments that intentionally reduce enrollment-token lifetime, any authenticated operator who can create a host through the Web UI can still mint a bearer enrollment token valid for about 24 hours.

Details

Enrollment tokens are bearer credentials for the public POST /api/v1/enroll endpoint: possession of a valid token allows enrolling the pending host and receiving a signed Nebula certificate/config for that host. The server configuration documents a security knob for their default lifetime and per-network overrides:

internal/config/server.go:82 defines EnrollmentTokenTTL as the default lifetime for freshly minted enrollment tokens.
internal/config/server.go:83 documents per-network overrides in network_config under enrollment_token_ttl.

The API server implements and consistently uses this resolver:

internal/api/server.go:77 defines tokenTTLFor, with precedence of per-network enrollment_token_ttl, then server default, then 24h fallback.
internal/api/server.go:82 reads network_config.enrollment_token_ttl.
internal/api/server.go:89 falls back to the configured server default.
internal/api/hosts.go:190 through internal/api/hosts.go:196 use now.Add(s.tokenTTLFor(r.Context(), host.NetworkID)) for API host creation.

The Web UI sibling path does not call the resolver and instead always sets a 24-hour expiry:

internal/web/handlers.go:874 mints the raw token for POST /ui/hosts.
internal/web/handlers.go:879 sets ExpiresAt: now.Add(24 * time.Hour).

This creates inconsistent behavior between API and Web UI host creation and bypasses an operator-configured token lifetime policy. The issue is reachable by an authenticated Web UI operator who can create hosts. Admins can create hosts in any network; non-admin operators can create hosts in networks whose CA they own.

Affected version evidence: the configurable enrollment-token TTL feature was introduced by commit 6c344a6 (feat(api): configurable enrollment-token TTL + regenerate endpoint (#75) (#79)), and git tag --contains 6c344a6 --sort=version:refname returns v0.3.0 through v0.3.8. Pattern checks across all release tags showed the TTL config/API resolver and the Web UI 24-hour hardcode are present in every v0.3.x release from v0.3.0 to v0.3.8, and are not meaningfully applicable to v0.1.x/v0.2.0 because the TTL policy knob was not present there. The current checkout at commit d92dd9a60de291e2bc1caf73b4e9a99567b31ec0 (git describe: v0.3.8-1-gd92dd9a) remains affected.

PoC

Safe local PoC run from a clean checkout at commit d92dd9a60de291e2bc1caf73b4e9a99567b31ec0 on 2026-06-12. The PoC is a temporary Go test that uses only in-memory SQLite and httptest; it does not start a real server and does not contact external services.

Create a temporary test file internal/web/security_audit_poc_test.go in package web.
In the test, create an in-memory Web UI with newTestWeb(t), create a network audit-poc-net with CIDR 10.77.0.0/24, and set network_config.enrollment_token_ttl to 30m.
Log in as the seeded test admin through the normal Web UI helper and obtain a CSRF token from GET /ui/hosts/new.
Submit POST /ui/hosts with network_id=audit-poc-net, name=audit-poc-host, nebula_ips=10.77.0.10, role=host, and kind=agent.
Parse the one-shot enrollment token from the returned host-detail page and read the token row with GetEnrollmentToken.
Compare the observed expiry to the configured 30-minute network override.

Command run:

go test ./internal/web -run 'TestSecurityAuditPOC' -count=1 -v

Observed vulnerable output from this environment:

=== RUN   TestSecurityAuditPOC_UIHostCreateIgnoresNetworkEnrollmentTokenTTL
POC_UI_TTL_BYPASS observed_token_ttl=24h0m0s configured_network_ttl=30m expires_at=2026-06-13T14:51:45Z
--- PASS: TestSecurityAuditPOC_UIHostCreateIgnoresNetworkEnrollmentTokenTTL (0.05s)

The meaningful control is the API sibling: internal/api/hosts.go:190 through internal/api/hosts.go:196 uses s.tokenTTLFor(...), and existing tests in internal/api/hosts_token_ttl_test.go verify API-created/regenerated enrollment tokens honor server-default and per-network TTLs. Variant review also found API regenerate-token, API re-enroll, and signed-poll rekey token minting use the resolver rather than a hardcoded 24h value. After recording the output, the temporary test file was removed and git status --short returned clean. The PoC was re-run after drafting this report and produced the output shown above.

Impact

An authenticated Web UI operator can bypass a configured enrollment-token lifetime policy and obtain a token valid for approximately 24 hours even when the deployment or network is configured for a much shorter lifetime such as 30 minutes. Because enrollment tokens are bearer credentials for the public enrollment endpoint, longer-than-intended validity increases the window in which a copied, logged, shared, or otherwise exposed token can be used to enroll the pending host and obtain its Nebula certificate/config. This weakens confidentiality and integrity for deployments relying on short token lifetimes to reduce enrollment-token exposure.

Suggested remediation: refactor the Web UI host-creation path to use the same TTL resolution as the API path, or move the resolver into a shared package/service used by both API and Web UI. Add a regression test under internal/web that sets network_config.enrollment_token_ttl = "30m", creates an agent host through POST /ui/hosts, and asserts the persisted enrollment token expires within the configured 30-minute window rather than 24 hours.

Severity

5.4 (Medium)


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

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/forgekeep/nebula-mesh"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.3.0"
            },
            {
              "fixed": "0.5.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-55513"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-613"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-14T20:26:21Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "### Summary\nThe `nebula-mgmt` Web UI host-creation path ignores both the server-wide `enrollment_token_ttl` security setting and per-network `network_config.enrollment_token_ttl` overrides. API host creation and token-regeneration paths use the configured TTL resolver, but `POST /ui/hosts` hardcodes `now.Add(24 * time.Hour)` for newly minted agent enrollment tokens. In deployments that intentionally reduce enrollment-token lifetime, any authenticated operator who can create a host through the Web UI can still mint a bearer enrollment token valid for about 24 hours.\n\n### Details\nEnrollment tokens are bearer credentials for the public `POST /api/v1/enroll` endpoint: possession of a valid token allows enrolling the pending host and receiving a signed Nebula certificate/config for that host. The server configuration documents a security knob for their default lifetime and per-network overrides:\n\n- `internal/config/server.go:82` defines `EnrollmentTokenTTL` as the default lifetime for freshly minted enrollment tokens.\n- `internal/config/server.go:83` documents per-network overrides in `network_config` under `enrollment_token_ttl`.\n\nThe API server implements and consistently uses this resolver:\n\n- `internal/api/server.go:77` defines `tokenTTLFor`, with precedence of per-network `enrollment_token_ttl`, then server default, then 24h fallback.\n- `internal/api/server.go:82` reads `network_config.enrollment_token_ttl`.\n- `internal/api/server.go:89` falls back to the configured server default.\n- `internal/api/hosts.go:190` through `internal/api/hosts.go:196` use `now.Add(s.tokenTTLFor(r.Context(), host.NetworkID))` for API host creation.\n\nThe Web UI sibling path does not call the resolver and instead always sets a 24-hour expiry:\n\n- `internal/web/handlers.go:874` mints the raw token for `POST /ui/hosts`.\n- `internal/web/handlers.go:879` sets `ExpiresAt: now.Add(24 * time.Hour)`.\n\nThis creates inconsistent behavior between API and Web UI host creation and bypasses an operator-configured token lifetime policy. The issue is reachable by an authenticated Web UI operator who can create hosts. Admins can create hosts in any network; non-admin operators can create hosts in networks whose CA they own.\n\nAffected version evidence: the configurable enrollment-token TTL feature was introduced by commit `6c344a6` (`feat(api): configurable enrollment-token TTL + regenerate endpoint (#75) (#79)`), and `git tag --contains 6c344a6 --sort=version:refname` returns `v0.3.0` through `v0.3.8`. Pattern checks across all release tags showed the TTL config/API resolver and the Web UI 24-hour hardcode are present in every `v0.3.x` release from `v0.3.0` to `v0.3.8`, and are not meaningfully applicable to `v0.1.x`/`v0.2.0` because the TTL policy knob was not present there. The current checkout at commit `d92dd9a60de291e2bc1caf73b4e9a99567b31ec0` (`git describe`: `v0.3.8-1-gd92dd9a`) remains affected.\n\n### PoC\nSafe local PoC run from a clean checkout at commit `d92dd9a60de291e2bc1caf73b4e9a99567b31ec0` on 2026-06-12. The PoC is a temporary Go test that uses only in-memory SQLite and `httptest`; it does not start a real server and does not contact external services.\n\n1. Create a temporary test file `internal/web/security_audit_poc_test.go` in package `web`.\n2. In the test, create an in-memory Web UI with `newTestWeb(t)`, create a network `audit-poc-net` with CIDR `10.77.0.0/24`, and set `network_config.enrollment_token_ttl` to `30m`.\n3. Log in as the seeded test admin through the normal Web UI helper and obtain a CSRF token from `GET /ui/hosts/new`.\n4. Submit `POST /ui/hosts` with `network_id=audit-poc-net`, `name=audit-poc-host`, `nebula_ips=10.77.0.10`, `role=host`, and `kind=agent`.\n5. Parse the one-shot enrollment token from the returned host-detail page and read the token row with `GetEnrollmentToken`.\n6. Compare the observed expiry to the configured 30-minute network override.\n\nCommand run:\n\n```bash\ngo test ./internal/web -run \u0027TestSecurityAuditPOC\u0027 -count=1 -v\n```\n\nObserved vulnerable output from this environment:\n\n```text\n=== RUN   TestSecurityAuditPOC_UIHostCreateIgnoresNetworkEnrollmentTokenTTL\nPOC_UI_TTL_BYPASS observed_token_ttl=24h0m0s configured_network_ttl=30m expires_at=2026-06-13T14:51:45Z\n--- PASS: TestSecurityAuditPOC_UIHostCreateIgnoresNetworkEnrollmentTokenTTL (0.05s)\n```\n\nThe meaningful control is the API sibling: `internal/api/hosts.go:190` through `internal/api/hosts.go:196` uses `s.tokenTTLFor(...)`, and existing tests in `internal/api/hosts_token_ttl_test.go` verify API-created/regenerated enrollment tokens honor server-default and per-network TTLs. Variant review also found API regenerate-token, API re-enroll, and signed-poll rekey token minting use the resolver rather than a hardcoded 24h value. After recording the output, the temporary test file was removed and `git status --short` returned clean. The PoC was re-run after drafting this report and produced the output shown above.\n\n### Impact\nAn authenticated Web UI operator can bypass a configured enrollment-token lifetime policy and obtain a token valid for approximately 24 hours even when the deployment or network is configured for a much shorter lifetime such as 30 minutes. Because enrollment tokens are bearer credentials for the public enrollment endpoint, longer-than-intended validity increases the window in which a copied, logged, shared, or otherwise exposed token can be used to enroll the pending host and obtain its Nebula certificate/config. This weakens confidentiality and integrity for deployments relying on short token lifetimes to reduce enrollment-token exposure.\n\nSuggested remediation: refactor the Web UI host-creation path to use the same TTL resolution as the API path, or move the resolver into a shared package/service used by both API and Web UI. Add a regression test under `internal/web` that sets `network_config.enrollment_token_ttl = \"30m\"`, creates an agent host through `POST /ui/hosts`, and asserts the persisted enrollment token expires within the configured 30-minute window rather than 24 hours.",
  "id": "GHSA-g4x6-jcvr-9m3g",
  "modified": "2026-07-14T20:26:21Z",
  "published": "2026-07-14T20:26:21Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/forgekeep/nebula-mesh/security/advisories/GHSA-g4x6-jcvr-9m3g"
    },
    {
      "type": "WEB",
      "url": "https://github.com/forgekeep/nebula-mesh/commit/514006029e09f1991122b86a80e7b25970bcfa98"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/forgekeep/nebula-mesh"
    },
    {
      "type": "WEB",
      "url": "https://github.com/forgekeep/nebula-mesh/releases/tag/v0.5.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "nebula-mesh: Web UI host creation ignores configured enrollment token TTL and mints 24-hour bearer enrollment tokens"
}

CVE-2026-55513 (GCVE-0-2026-55513)

Vulnerability from cvelistv5 – Published: 2026-09-04 19:43 – Updated: 2026-09-08 17:32

Title

nebula-mesh: Web UI host creation ignores configured enrollment token TTL and mints 24-hour bearer enrollment tokens

Summary

nebula-mesh is a self-hosted control plane for Slack Nebula mesh VPN. From version 0.3.0 to before version 0.5.0, the nebula-mgmt Web UI host-creation path ignores both the server-wide enrollment_token_ttl security setting and per-network network_config.enrollment_token_ttl overrides. API host creation and token-regeneration paths use the configured TTL resolver, but POST /ui/hosts hardcodes now.Add(24 * time.Hour) for newly minted agent enrollment tokens. In deployments that intentionally reduce enrollment-token lifetime, any authenticated operator who can create a host through the Web UI can still mint a bearer enrollment token valid for about 24 hours. This issue has been patched in version 0.5.0.

Severity

5.4 (Medium)


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

SSVC

Exploitation: poc Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-08 17:31 UTC

CWE

CWE-613 - Insufficient Session Expiration

Assigner

GitHub_M mitre root Scorecard

References

3 references

URL	Tags
https://github.com/forgekeep/nebula-mesh/security…	x_refsource_CONFIRM
https://github.com/forgekeep/nebula-mesh/commit/5…	x_refsource_MISC
https://github.com/forgekeep/nebula-mesh/releases…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
forgekeep	nebula-mesh	Affected: >= 0.3.0, < 0.5.0

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-55513",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-09-08T17:31:11.061279Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-09-08T17:32:25.373Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://github.com/forgekeep/nebula-mesh/security/advisories/GHSA-g4x6-jcvr-9m3g"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "nebula-mesh",
          "vendor": "forgekeep",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 0.3.0, \u003c 0.5.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "nebula-mesh is a self-hosted control plane for Slack Nebula mesh VPN. From version 0.3.0 to before version 0.5.0, the nebula-mgmt Web UI host-creation path ignores both the server-wide enrollment_token_ttl security setting and per-network network_config.enrollment_token_ttl overrides. API host creation and token-regeneration paths use the configured TTL resolver, but POST /ui/hosts hardcodes now.Add(24 * time.Hour) for newly minted agent enrollment tokens. In deployments that intentionally reduce enrollment-token lifetime, any authenticated operator who can create a host through the Web UI can still mint a bearer enrollment token valid for about 24 hours. This issue has been patched in version 0.5.0."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 5.4,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "integrityImpact": "LOW",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-613",
              "description": "CWE-613: Insufficient Session Expiration",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-04T19:43:18.876Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/forgekeep/nebula-mesh/security/advisories/GHSA-g4x6-jcvr-9m3g",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/forgekeep/nebula-mesh/security/advisories/GHSA-g4x6-jcvr-9m3g"
        },
        {
          "name": "https://github.com/forgekeep/nebula-mesh/commit/514006029e09f1991122b86a80e7b25970bcfa98",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/forgekeep/nebula-mesh/commit/514006029e09f1991122b86a80e7b25970bcfa98"
        },
        {
          "name": "https://github.com/forgekeep/nebula-mesh/releases/tag/v0.5.0",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/forgekeep/nebula-mesh/releases/tag/v0.5.0"
        }
      ],
      "source": {
        "advisory": "GHSA-g4x6-jcvr-9m3g",
        "discovery": "UNKNOWN"
      },
      "title": "nebula-mesh: Web UI host creation ignores configured enrollment token TTL and mints 24-hour bearer enrollment tokens"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-55513",
    "datePublished": "2026-09-04T19:43:18.876Z",
    "dateReserved": "2026-06-16T22:44:22.283Z",
    "dateUpdated": "2026-09-08T17:32:25.373Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

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Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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Action not permitted

GHSA-G4X6-JCVR-9M3G

Summary

Details

PoC

Impact

CVE-2026-55513 (GCVE-0-2026-55513)

Tags

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