CVE-2026-55512

MEDIUMPre-NVD 5.35.3
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

This medium-severity CVE scores 5.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.6% (47th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
Elevated
5.3EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.6%CVSS: 5.3Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

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
5.3MEDIUMmedium confidence
EG Risk
55
EG Risk 55/100

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 (value × EchelonGraph’s weight)
Severity53% × 45%
The EG Score, 5.3 of 10.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.6%
EPSS %ILE
47th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; 60 days if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

July 14, 2026

Last Modified

September 9, 2026

Advisory Details (3)

Auto-updated Sep 4, 2026
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 advisoryMentions a patch (unverified)

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 rangeFix by version rangeDependents
github.com/forgekeep/nebula-mesh—
  • 0.2.0 up to 0.5.0: fixed in 0.5.0
  • 0.4.0 up to 0.5.0: fixed in 0.5.0
—
github.com/juev/nebula-mesh—
  • 0.2.0 on: no fix on record
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 11× in last 7d / 35× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

  1. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  2. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  3. 2026-10-12 15:55 UTCEG score recompute
  4. 2026-10-11 19:39 UTCEG score recompute
  5. 2026-10-11 16:54 UTCEG score recompute
  6. 2026-10-11 14:17 UTCEG score recompute
  7. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  8. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  9. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  10. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  11. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  12. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  13. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  14. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  15. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  16. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  17. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  18. 2026-10-01 12:50 UTCEG score recompute
  19. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  20. 2026-09-29 15:22 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  21. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  22. 2026-09-28 08:52 UTCEG score recompute
  23. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  24. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  25. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.6% · 46th percentile
Show 28 more
  1. 2026-09-24 08:58 UTCEG score recompute
  2. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  3. 2026-09-23 03:26 UTCEG score recompute
  4. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  5. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  6. 2026-09-18 04:49 UTCEG score recompute
  7. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  8. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  9. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  10. 2026-09-15 03:11 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  11. 2026-09-14 09:11 UTCEG score recompute
  12. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  13. 2026-09-13 07:29 UTCEG score recompute
  14. 2026-09-11 21:52 UTCEG score recompute
  15. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  16. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  17. 2026-09-09 16:54 UTCEG score recompute
  18. 2026-09-09 16:04 UTCEG score recompute
  19. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  20. 2026-09-08 01:04 UTCEG score recompute
  21. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  22. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  23. 2026-09-05 22:29 UTCEG score recompute
  24. 2026-09-04 20:30 UTCEG score recompute
  25. 2026-07-30 19:02 UTCEG score recompute
  26. 2026-07-26 11:41 UTCEG score recompute
  27. 2026-07-23 03:20 UTCEG score recompute
  28. 2026-07-14 20:56 UTCEG score recompute

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-55512?
CVE-2026-55512 is a medium-severity vulnerability; its CVE record was 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 the CVE record for CVE-2026-55512 published?
The CVE record for CVE-2026-55512 was published on July 14, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 9, 2026; the record at its source may have been updated since.
Is CVE-2026-55512 actively exploited?
CVE-2026-55512 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.6% probability of exploitation in the next 30 days (47th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-55512?
CVE-2026-55512 has a CVSS base score of 5.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-55512?
A fix for CVE-2026-55512 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-55512 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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