What is CVE-2026-63464?

CVE-2026-63464 is a high-severity vulnerability, classified under Missing Authorization. CVSS score: 7.7/10. Published 2026-09-04.

How severe is CVE-2026-63464?

High severity. CVSS v3 base score is 7.7 out of 10.

CVE-2026-63464

CVE-2026-63464

nebula-mesh is a self-hosted control plane for Slack Nebula mesh VPN. From version 0.6.0 to before version 0.7.2, non-admin operators (role user) can set allow_private: true on their own managed webhook subscription (POST/PATCH /api/v1/webhook-subscriptions). No admin check exists on this field. At delivery time, allow_private switches the dispatcher to an unguarded HTTP client, bypassing the private/loopback/link-local SSRF guard — letting a low-privilege operator make the server request internal addresses. This issue has been patched in version 0.7.2.

Vulnerability class: Broken Access Control

CVSS v3 metric

CVSS v3 base score 7.7 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N.

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-63464?: CVE-2026-63464 is a high-severity vulnerability, classified under Missing Authorization. CVSS score: 7.7/10. Published 2026-09-04.
How severe is CVE-2026-63464?: High severity. CVSS v3 base score is 7.7 out of 10.