High severity · published Jul 28, 2026
CVE-2026-49258
Nebula Mesh: Web UI lacks ownership checks, enabling cross-operator access to hosts and networks (read, block, delete)
8.8
CVSS
0.5%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 41% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
NE
nebula-mesh · juev
< 0.3.6 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-49258
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-49258
github.com
https://github.com/forgekeep/nebula-mesh/pull/161
github.com
https://github.com/forgekeep/nebula-mesh/security/advisories/GHSA-c6v2-3ffm-vcmc
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