What is CVE-2026-49258?

CVE-2026-49258 is a high-severity vulnerability in Juev Nebula-Mesh, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 8.8/10. Published 2026-07-28.

How severe is CVE-2026-49258?

High severity. CVSS v3 base score is 8.8 out of 10.

Auth bypass in Juev Nebula-Mesh

CVE-2026-49258

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.

Vulnerability class: IDOR (Insecure Direct Object Reference)

EPSS: 0.003 (20.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Affected products

Juev Nebula-mesh — versions < 0.3.6

Weakness classification (CWE)

References

security-advisories@github.com (x_refsource_CONFIRM)
security-advisories@github.com (x_refsource_MISC)

Frequently asked questions

What is CVE-2026-49258?: CVE-2026-49258 is a high-severity vulnerability in Juev Nebula-Mesh, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 8.8/10. Published 2026-07-28.
How severe is CVE-2026-49258?: High severity. CVSS v3 base score is 8.8 out of 10.