Vulnerability · Published Sep 4, 2026 · Assigned by GitHub_M
CVE-2026-61699nebula-mesh: Certificate revocation is never enforced at the mesh
High 8.1
In plain English
A high-severity security flaw in nebula-mesh from forgekeep. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 39% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
nebula-mesh is a self-hosted control plane for Slack Nebula mesh VPN. Prior to version 0.7.1, revocation is the only in-band mechanism that isolates a compromised/offboarded host from a Nebula mesh. Because the blocklist never reaches any peer's config.yml, a Blocked host retains full overlay reachability to every peer under its CA (and internal services on the mesh) for up to 30d (agent) / 365d (mobile). An attacker who exfiltrates host.key+host.crt can run stock slackhq/nebula directly, ignore the agent's 403/410 poll responses, and stay connected after the operator revokes the host. Operator-visible state (UI shows blocked, audit log records it) is misleading. This issue has been patched in version 0.7.1.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/forgekeep/nebula-mesh | 0.7.1 | GHSA-cm26-5974-52h8 |
| Go | github.com/forgekeep/nebula-mesh | 0.7.1 | GO-2026-5986 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| forgekeep | nebula-mesh | < 0.7.1 |
Weakness: CWE-299, CWE-672 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N