CVE-2026-53603

HIGHPre-NVD 7.17.1—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 89% 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
7.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.1Exploit: None knownExposed: 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. Prior to version 0.3.8, Operator session tokens are stored in plaintext in the operator_sessions table (the token column is the PRIMARY KEY). The session token is a 32-byte random hex value sent directly in a cookie and valid for 24 hours. Anyone who can read the database (backup, snapshot, file copy, or SQL-level disclosure) obtains every active session token and can hijack operator sessions directly, with no further authentication. This issue has been patched in version 0.3.8.

CVSS v3
7.1
EG Score
7.1(medium)
EG Risk
47(Track)
EG Risk 47/100SSVC: Track

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
Severity71% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
11%
KEV
Not listed

Published

July 14, 2026

Last Modified

September 8, 2026

Advisory Details (3)

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

v0.3.8

Patch available: forgekeep/nebula-mesh v0.3.8

https://github.com/forgekeep/nebula-mesh/releases/tag/v0.3.8
github_commit

commit 7cb01bab281d (forgekeep/nebula-mesh)

Fix landed in forgekeep/nebula-mesh commit 7cb01bab281d — awaiting tagged release

https://github.com/forgekeep/nebula-mesh/commit/7cb01bab281ded557f8b6c81dab5f48d4c10182e
github Patch Available

Operator session tokens stored in plaintext in the database · Advisory · forgekeep/nebula-mesh · GitHub

https://github.com/forgekeep/nebula-mesh/security/advisories/GHSA-q4vm-pq3q-8wgq

Vendor Advisories for CVE-2026-53603(1)

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

Affected Packages

(1 across 1 ecosystem)
Go(1)
PackageVulnerable rangeFixed inDependents
github.com/forgekeep/nebula-mesh—0.3.8—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 19× 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. 2026-09-16 14:08 UTCEPSS rescore
  4. 2026-09-16 05:15 UTCEPSS rescore
  5. 2026-09-13 23:15 UTCEG score recompute
  6. 2026-09-13 16:47 UTCEPSS rescore
  7. 2026-09-13 07:29 UTCEG score recompute
  8. 2026-09-11 21:52 UTCEG score recompute
  9. 2026-09-11 14:53 UTCEPSS rescore
  10. 2026-09-10 09:35 UTCEPSS rescore
  11. 2026-09-08 22:01 UTCEPSS rescore
  12. 2026-09-08 20:24 UTCEG score recompute
  13. 2026-09-08 01:04 UTCEG score recompute
  14. 2026-09-07 16:01 UTCEPSS rescore
  15. 2026-09-06 13:47 UTCEPSS rescore
  16. 2026-09-05 20:55 UTCEG score recompute
  17. 2026-09-04 20:30 UTCEG score recompute
  18. 2026-09-04 19:45 UTCEG score recompute▲ 7.10
  19. 2026-09-04 19:44 UTCMITRE cvelistV5CVSS v3 → 7.1 · CVSS v4 → 7.1
  20. 2026-08-01 00:38 UTCEG score recompute
  21. 2026-07-26 11:41 UTCEG score recompute
  22. 2026-07-23 03:19 UTCEG score recompute
  23. 2026-07-14 20:56 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-53603?
CVE-2026-53603 is a high vulnerability published on July 14, 2026. nebula-mesh is a self-hosted control plane for Slack Nebula mesh VPN. Prior to version 0.3.8, Operator session tokens are stored in plaintext in the operator_sessions table (the token column is the PRIMARY KEY). The session token is a 32-byte random hex value sent directly in a cookie and valid for…
When was CVE-2026-53603 disclosed?
CVE-2026-53603 was first published in the National Vulnerability Database on July 14, 2026, with the most recent update on September 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-53603 actively exploited?
CVE-2026-53603 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 89.3% of all scored CVEs.
What is the CVSS score of CVE-2026-53603?
CVE-2026-53603 has a CVSS v3 base score of 7.1 (NVD).
How do I remediate CVE-2026-53603?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-53603, 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-2026-53603

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