CVE-2026-61699
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.25%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 8.1 HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
- EPSS
- 0.25% probability · 16th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-299, CWE-672
- Source
- security-advisories@github.com
References
- https://github.com/forgekeep/nebula-mesh/commit/0426e2f224a9b1e2029029bf923c93ed39d21cdb
- https://github.com/forgekeep/nebula-mesh/releases/tag/v0.7.1
- https://github.com/forgekeep/nebula-mesh/security/advisories/GHSA-cm26-5974-52h8
- https://github.com/forgekeep/nebula-mesh/security/advisories/GHSA-cm26-5974-52h8
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.