# CVE-2026-49258: Nebula Mesh: Web UI lacks ownership checks, enabling cross-operator access to hosts and networks (read, block, delete)

> Authenticated non-admin operators can access, block, or delete other operators' hosts and networks due to missing ownership checks in the web UI.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 28 Jul 2026
- **Updated:** 28 Jul 2026
- **Also known as:** GHSA-c6v2-3ffm-vcmc, GO-2026-5816

## What is CVE-2026-49258?

CVE-2026-49258 is a high-severity missing authorization vulnerability in juev nebula-mesh, published on 28 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Nebula Mesh is a self-hosted control plane for the Slack Nebula mesh VPN. In versions 0.3.5 and below, the web UI (/ui/*) does not apply the per-operator CA scoping employed by the JSON API. This was partially addressed by GHSA-598g-h2vc-h5vg, but the changes were not implemented in the web read/mutation surface. Any authenticated non-admin operator (for example, one created via self-registration or OIDC) can access resources belonging to other operators. The host create/edit/mobile-bundle/network-create paths and all CA-management routes were already correctly scoped. A malicious operator could block or delete any other operator's host, or read any operator's hosts and networks. This issue has been fixed in version 0.3.6.

Weakness: CWE-862 (Missing Authorization), CWE-639 (Authorization Bypass Through User-Controlled Key)

## Which versions are affected by CVE-2026-49258?

3 open source packages ship an affected version, including github.com/juev/nebula-mesh.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/juev/nebula-mesh` | Go | All versions | None |
| `github.com/juev/nebula-mesh` | Go | All versions to 0.3.4 | None |
| `github.com/juev/nebula-mesh` | Go | All versions to 0.3.4 | None |

## How do I fix CVE-2026-49258?

Upgrade to a fixed version.

## Is CVE-2026-49258 being exploited?

There is no known exploitation of CVE-2026-49258 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-49258 and fix it if it is affected.

What it is: CVE-2026-49258 is a high-severity missing authorization vulnerability in juev nebula-mesh, published on 28 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-49258 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/juev/nebula-mesh (Go): affected all versions; no fix listed
- github.com/juev/nebula-mesh (Go): affected all versions up to 0.3.4; no fix listed
- github.com/juev/nebula-mesh (Go): affected all versions up to 0.3.4; no fix listed

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-49258/ (Markdown: https://insights.sbomify.com/CVE-2026-49258/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-49258
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-49258
- OSV: https://osv.dev/vulnerability/CVE-2026-49258

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-49258/
Summaries are generated and may contain mistakes; the official description above is the record.