CVE-2026-55512 Details
Description
nebula-mesh is a self-hosted control plane for Slack Nebula mesh VPN. From version 0.2.0 to before version 0.5.0, when OIDC is enabled, GET /ui/oidc/login is reachable without authentication and is registered outside the Web UI rate-limited auth routes. Every request creates a fresh random OIDC state value and stores it in an in-memory map for 10m. Expired states are swept lazily, but there is no rate limit or maximum live-state cap on the allocation path. An unauthenticated remote client can therefore grow OIDC.states for the full state TTL, bounded by request throughput rather than by configured auth rate limits. This issue has been patched in version 0.5.0.
A vulnerability exists in Nebula Mesh versions 0.2.0 prior to 0.5.0, when OpenID Connect (OIDC) is enabled. The issue arises because the OIDC login endpoint can be accessed without authentication, and it is not protected by the same rate limits as other authentication routes. Each unauthenticated request to the login endpoint generates a new OIDC state value, which is stored in memory for 10 minutes. There is no limit on the number of states that can be created, allowing an attacker to flood the server with requests and exhaust memory resources. This vulnerability has been patched in version 0.5.0.
Users can update to Nebula Mesh version 0.5.0 or later, where this vulnerability has been fixed. For those using earlier versions, it is recommended to apply the 'auth' rate limiter to the OIDC login route and to set a maximum limit on the number of concurrent OIDC states that can be allocated.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Sep 4, 2026CISA-ADP
Assessed Sep 9, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/forgekeep/nebula-mesh/security/advisories/GHSA-m3cx-mwpg-32jg | CISA-ADP | AdvisoryExploitRemedyVendor |
| https://github.com/forgekeep/nebula-mesh/commit/bc387086cc0e4b9c1654468b7391af19cacfe367 | [email protected] | Source CodeVendor |
| https://github.com/forgekeep/nebula-mesh/releases/tag/v0.5.0 | [email protected] | Release NotesVendor |
| https://github.com/forgekeep/nebula-mesh/security/advisories/GHSA-m3cx-mwpg-32jg | [email protected] | AdvisoryExploitRemedyVendor |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-400 | Uncontrolled Resource Consumption | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| forgekeep nebula-mesh | >= 0.2.0, < 0.5.0 (semver) |
CPE
Remediation
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Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Sep 9, 2026 | CVE Modified | CISA-ADP |
| Sep 4, 2026 | New CVE Received | [email protected] |