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Fencer Intel
high 8.1

CVE-2026-61699 json

nebula-mesh: Certificate revocation is never enforced at the mesh

published 3mo ago modified 2mo ago also GHSA-cm26-5974-52h8 , GO-2026-5986 , EUVD-2026-71720

cvss
8.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 39%
public exploits
0
none known

Summary

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.

Patch / fix

  • go github.com/forgekeep/nebula-mesh 0.7.1
  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

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CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
2mo ago

Exploit prediction

0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-11).

Exploits and checks

  • github.com https://github.com/forgekeep/nebula-mesh/security/advisories/GHSA-cm26-5974-52h8 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
GitHub 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Affected packages

ecosystem package affected fixed in
go github.com/forgekeep/nebula-mesh
<0.7.1
0.7.1

Affected products

  • forgekeep nebula-mesh

Classification

Weakness
  • CWE-299 Improper Check for Certificate Revocation
  • CWE-672 Operation on a Resource after Expiration or Release

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.