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.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
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.
Which versions are affected by CVE-2026-49258?
3 open source packages ship an affected version, including github.com/juev/nebula-mesh.
| Package | 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.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-49258 being exploited?
There is no known exploitation of CVE-2026-49258 in the wild and no public exploit code.
Sources
Also known as GHSA-c6v2-3ffm-vcmc, GO-2026-5816.