CVE-2026-55512
nebula-mesh: Unauthenticated OIDC login endpoint allocates unbounded in-memory state entries without rate limiting
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.
INFO
Published Date :
Sept. 4, 2026, 8:17 p.m.
Last Modified :
Sept. 4, 2026, 8:17 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-55512
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update nebula-mesh to version 0.5.0.
- Apply patches for versions before 0.5.0.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-55512.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-55512 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-55512
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-55512 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-55512 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Sep. 04, 2026
Action Type Old Value New Value Added 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. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L Added CWE CWE-400 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/55xxx/CVE-2026-55512.json">CVE-2026-55512</a> Added Reference https://github.com/forgekeep/nebula-mesh/commit/bc387086cc0e4b9c1654468b7391af19cacfe367 Added Reference https://github.com/forgekeep/nebula-mesh/releases/tag/v0.5.0 Added Reference https://github.com/forgekeep/nebula-mesh/security/advisories/GHSA-m3cx-mwpg-32jg