CVE-2026-55513Medium· 5.4▾ TwilightPoC available

nebula-mesh is a self-hosted control plane for Slack Nebula mesh VPN

▾ Twilight zone — High severity, or a signal on a lesser flaw

Depth score42/ 100 · Moderate

impact 29.7 · likelihood 0 · exploitation 12

⚡ Agent-ready:Raw markdown ↗JSON ↗

Proof of concept

A public proof-of-concept already exists for this vulnerability — see Exploit availability below.

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Published

Sep 4, 2026

Updated

Sep 8, 2026

CVSS

5.4

Vendor

forgekeep

Product

nebula-mesh

CWE

CWE-613

Depth score

42 · Moderate

EPSS

0.19% · p9

Platforms

—

Source

NVD

Vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

CISA SSVC

decided 2026-09-08

Exploitation: poc
Automatable: no
Technical impact: partial

Stakeholder-Specific Vulnerability Categorization from CISA's ADP record at CVE.org: whether exploitation is observed, whether an attack can be automated, and how much of the system is at stake.

EPSS history

Exploit-prediction probability, daily snapshots since Sep 5.

0.2% → 0.2%

Timeline

Disclosure to exploitation, from the record and what we observed since indexing it.

4 events · 5 days

Sep 4, 2026Published
Disclosed via NVD
Sep 5, 2026EPSS first tracked
0.2%
Sep 8, 2026Record revised
Last analysed / modified upstream
Sep 8, 2026Public exploit observed
Exploit / PoC code exists

forgekeep CWE-613 #nvd #cve.org #exploit-available #ghsa #go

Affected

nebula-mesh >= 0.3.0, < 0.5.0

Patched in

github.com/forgekeep/nebula-mesh 0.5.0

Full technical detail▾

Overview

nebula-mesh is a self-hosted control plane for Slack Nebula mesh VPN. From version 0.3.0 to before version 0.5.0, the nebula-mgmt Web UI host-creation path ignores both the server-wide enrollment_token_ttl security setting and per-network network_config.enrollment_token_ttl overrides. API host creation and token-regeneration paths use the configured TTL resolver, but POST /ui/hosts hardcodes now.Add(24 * time.Hour) for newly minted agent enrollment tokens. In deployments that intentionally reduce enrollment-token lifetime, any authenticated operator who can create a host through the Web UI can still mint a bearer enrollment token valid for about 24 hours. This issue has been patched in version 0.5.0.

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

Package advisory (CVE-2026-55513)

Affected packages:

github.com/forgekeep/nebula-mesh >= 0.3.0, < 0.5.0

Patched in:

github.com/forgekeep/nebula-mesh 0.5.0

Source: https://github.com/advisories/GHSA-g4x6-jcvr-9m3g

References

Change history

Field changes observed since this record was first indexed.

Sep 9, 2026Public exploit / PoC published
Sep 9, 2026Public exploit flag cleared
Sep 9, 2026Public exploit / PoC published
Sep 9, 2026Public exploit flag cleared
Sep 9, 2026Public exploit / PoC published
Sep 8, 2026Public exploit flag cleared
Sep 8, 2026Public exploit / PoC published
Sep 8, 2026Public exploit flag cleared
Sep 8, 2026Public exploit / PoC published
Sep 8, 2026Public exploit flag cleared
Sep 8, 2026Public exploit / PoC published
Sep 8, 2026Public exploit flag cleared

Related vulnerabilities

Connected by shared product, vendor, weakness, or advisory.

#nvd#cve.org#exploit-available#ghsa#go

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