highCVSS 8.8Vulnerability

CVE-2026-49258

## Summary The web UI (`/ui/*`) does not apply the per-operator CA scoping the JSON API received for GHSA-598g-h2vc-h5vg. Any authenticated non-admin operator (for example, one created via self-registration or OIDC) can access resources belonging to other operators. ## Impact A non-admin operator can: - **Block or delete any other operator's host.** `POST /ui/hosts/{id}/block` and `DELETE /ui/hosts/{id}` act on the URL `id` with no ownership check, so a non-admin can block (revoking the host's certificate via the blocklist) or delete any host in the deployment — a cross-operator denial of service. - **Read every operator's hosts and networks.** The dashboard, `/ui/hosts`, the host detail page, `/ui/networks` (including the create-form error re-render), and the `/ui/events` stream all return data across all operators, exposing host names, Nebula IPs, public IPs, certificate fingerprints and expiry, and network names and CIDRs. This is the same cross-operator class as GHSA-598g; that remediation covered the JSON API but not the web read/mutation surface. The host create/edit/mobile-bundle/network-create paths and all CA-management routes were already correctly scoped. Affected handlers (`internal/web`): `handleHostDetail`, `handleHostBlock`, `handleHostDelete`, `handleDashboard`, `handlePartialStats`, `handleHosts`, `handleNetworks`, `renderNetworksError`, `handleHostEvents`. ## Conditions Exposure requires at least one non-admin operator to exist (self-registration enabled, OIDC, or an admin-created user). A single-admin deployment with no additional operators is not affected. ## Fix A complete candidate fix with regression tests is ready in a private repository shared with the maintainer (`ak2k/nebula-mesh-ghsa-web`, PR #1): scope these handlers to the session operator's owned CAs (admins keep the full view), mirroring the API's ownership checks.

Properties

summary
Nebula Mesh: Web UI lacks ownership checks, enabling cross-operator access to hosts and networks (read, block, delete)
severity
high
epss_score
0.00283
cvss_score
8.8
ghsa_published
2026-06-26T21:29:02Z
source_url
https://github.com/advisories/GHSA-c6v2-3ffm-vcmc
ghsa_updated
2026-06-26T21:29:03Z
ghsa_id
GHSA-c6v2-3ffm-vcmc
cve_id
CVE-2026-49258
cvss_vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
is_ghsa_only
false
epss_percentile
0.20452

Related Entities (6)

ENRICHED_BY (1)

[Source]FIRST EPSS

REPORTED_BY (1)

[Source]GitHub Advisory Database

VULNERABLE_TO (1)

[Software]go/github.com/juev/nebula-mesh

AFFECTS (1)

[Software]go/github.com/juev/nebula-mesh

HAS_WEAKNESS (2)

[Weakness]Authorization Bypass Through User-Controlled Key
[Weakness]Missing Authorization

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CVE-2026-49258 (CVSS 8.8) — Ninja Signal Threat Intelligence | Ninja Signal