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GHSA-c6v2-3ffm-vcmc

HighCVSS 8.8 / 10
Published Jun 26, 2026·Last modified Jun 26, 2026
Affected Components(0)

No affected components available

Description

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.

Risk Scores
Base Score
8.8

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker needs basic access or low-level privileges. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the confidentiality of the information. There is a high impact on the integrity of the data. There is a high impact on the availability of the system.

Threat Intelligence
8.1

Exploitation activity has been observed. Apply available patches or mitigations urgently.

EPSS
0.28%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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