CVE-2026-55513
Received Received - Intake

Authentication Bypass in Nebula-Mesh Web UI

Publication date: 2026-09-04

Last updated on: 2026-09-04

Assigner: GitHub, Inc.

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.

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Meta Information

Published
2026-09-04
Last Modified
2026-09-04
Generated
2026-09-05
AI Q&A
2026-09-04
EPSS Evaluated
N/A
NVD
CVE-2026-55513

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
nebula-mesh nebula-mgmt From 0.3.0 (inc) to 0.5.0 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-613 According to WASC, "Insufficient Session Expiration is when a web site permits an attacker to reuse old session credentials or session IDs for authorization."

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Executive Summary

This vulnerability in nebula-mesh allows authenticated operators to create host enrollment tokens with a hardcoded 24-hour validity period via the Web UI, ignoring configured shorter token lifetimes. The issue affects versions 0.3.0 to before 0.5.0.

Detection Guidance

This vulnerability can be detected by checking the version of nebula-mgmt. If your system is running a version between 0.3.0 and 0.5.0, it is vulnerable. Run: nebula-mgmt version to check the installed version.

Impact Analysis

An attacker with access could create long-lived enrollment tokens, potentially allowing unauthorized access to the VPN mesh for up to 24 hours. This could lead to network compromise or data breaches if tokens are leaked or misused.

Compliance Impact

This vulnerability may violate compliance requirements for access control and token expiration (e.g., GDPR's data protection principles or HIPAA's security rules) by allowing prolonged unauthorized access if tokens are compromised.

Mitigation Strategies

Upgrade nebula-mgmt to version 0.5.0 or later to patch the vulnerability. Review and enforce enrollment token TTL settings to ensure they are not bypassed via the Web UI.

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