CVE-2026-55512

MEDIUMPre-NVD 5.35.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 73% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Elevated
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.3Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
5.3
EG Score
5.3(medium)
EG Risk
55(Attend)
EG Risk 55/100SSVC: Attend

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity53% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
27%
KEV
Not listed

Published

July 14, 2026

Last Modified

September 9, 2026

Advisory Details (3)

Auto-updated Sep 4, 2026
🔬 Proof of concept available. Patch available. Sources: github_release, github, github_commit.
github_release Patch Available

v0.5.0

Patch available: forgekeep/nebula-mesh v0.5.0

https://github.com/forgekeep/nebula-mesh/releases/tag/v0.5.0
github_commit

commit bc387086cc0e (forgekeep/nebula-mesh)

Fix landed in forgekeep/nebula-mesh commit bc387086cc0e — awaiting tagged release

https://github.com/forgekeep/nebula-mesh/commit/bc387086cc0e4b9c1654468b7391af19cacfe367
github Patch Available🟡 PoC Available

Unauthenticated OIDC login endpoint allocates unbounded in-memory state entries without rate limiting · Advisory · forgekeep/nebula-mesh · GitHub

https://github.com/forgekeep/nebula-mesh/security/advisories/GHSA-m3cx-mwpg-32jg

Vendor Advisories for CVE-2026-55512(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(2 across 1 ecosystem)
Go(2)
PackageVulnerable rangeFixed inDependents
github.com/forgekeep/nebula-mesh—0.5.0—
github.com/juev/nebula-mesh———

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 9× in last 7d / 20× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-18 19:28 UTCEPSS rescore
  2. 2026-09-18 04:49 UTCEG score recompute
  3. 2026-09-17 19:31 UTCEPSS rescore
  4. 2026-09-16 14:08 UTCEPSS rescore
  5. 2026-09-16 05:15 UTCEPSS rescore
  6. 2026-09-15 03:11 UTCEPSS rescore
  7. 2026-09-14 09:11 UTCEG score recompute
  8. 2026-09-13 16:47 UTCEPSS rescore
  9. 2026-09-13 07:29 UTCEG score recompute
  10. 2026-09-11 21:52 UTCEG score recompute
  11. 2026-09-11 14:53 UTCEPSS rescore
  12. 2026-09-10 09:35 UTCEPSS rescore
  13. 2026-09-09 16:54 UTCEG score recompute
  14. 2026-09-09 16:04 UTCEG score recompute
  15. 2026-09-08 22:01 UTCEPSS rescore
  16. 2026-09-08 01:04 UTCEG score recompute
  17. 2026-09-07 16:01 UTCEPSS rescore
  18. 2026-09-06 13:47 UTCEPSS rescore
  19. 2026-09-05 22:29 UTCEG score recompute
  20. 2026-09-04 20:30 UTCEG score recompute
  21. 2026-07-30 19:02 UTCEG score recompute
  22. 2026-07-26 11:41 UTCEG score recompute
  23. 2026-07-23 03:20 UTCEG score recompute
  24. 2026-07-14 20:56 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-55512?
CVE-2026-55512 is a medium vulnerability published on July 14, 2026. 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…
When was CVE-2026-55512 disclosed?
CVE-2026-55512 was first published in the National Vulnerability Database on July 14, 2026, with the most recent update on September 9, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-55512 actively exploited?
CVE-2026-55512 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 73.3% of all scored CVEs.
What is the CVSS score of CVE-2026-55512?
CVE-2026-55512 has a CVSS v3 base score of 5.3 (NVD).
How do I remediate CVE-2026-55512?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-55512, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-55512

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