Vulnerability Database

362,176

Total vulnerabilities in the database

CVE-2026-49258 — github.com/juev/nebula-mesh

Authorization Bypass Through User-Controlled Key

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.

CVSS v3:

  • Severity: High
  • Score: 8.8
  • AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Frequently Asked Questions

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.