CVE-2026-53603

HIGHPre-NVD 7.17.1
EchelonGraph scoreMEDIUM confidence

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

This high-severity CVE scores 7.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4% (27th 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
7.1EG
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).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 7.1Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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
7.1HIGHmedium confidence
EG Risk
47
EG Risk 47/100

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)
Severity71% × 45%
The EG Score, 7.1 of 10.
Exploitation0.4% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
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 none (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
0.4%
EPSS %ILE
27th
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 none (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 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 advisoryMentions a patch (unverified)

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 rangeFix by version rangeDependents
github.com/forgekeep/nebula-mesh—
  • every version up to 0.3.8: fixed in 0.3.8
—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 11× in last 7d / 33× 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 0.4% · 27th percentile
  2. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  3. 2026-10-12 15:57 UTCEG score recompute
  4. 2026-10-11 19:40 UTCEG score recompute
  5. 2026-10-11 16:55 UTCEG score recompute
  6. 2026-10-11 14:18 UTCEG score recompute
  7. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  8. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  9. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  10. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  11. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  12. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  13. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  14. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  15. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  16. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  17. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  18. 2026-10-01 12:50 UTCEG score recompute
  19. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  20. 2026-09-29 15:22 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  21. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  22. 2026-09-28 08:52 UTCEG score recompute
  23. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  24. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  25. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.4% · 26th percentile
Show 27 more
  1. 2026-09-24 08:58 UTCEG score recompute
  2. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  3. 2026-09-23 03:26 UTCEG score recompute
  4. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  5. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  6. 2026-09-18 04:49 UTCEG score recompute
  7. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  8. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  9. 2026-09-13 23:15 UTCEG score recompute
  10. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  11. 2026-09-13 07:29 UTCEG score recompute
  12. 2026-09-11 21:52 UTCEG score recompute
  13. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  14. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  15. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  16. 2026-09-08 20:24 UTCEG score recompute
  17. 2026-09-08 01:04 UTCEG score recompute
  18. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  19. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  20. 2026-09-05 20:55 UTCEG score recompute
  21. 2026-09-04 20:30 UTCEG score recompute
  22. 2026-09-04 19:45 UTCEG score recomputeFirst assessed: 7.1 HIGH
  23. 2026-09-04 19:44 UTCMITRE cvelistV5CVSS v3 → 7.1 · CVSS v4 → 7.1
  24. 2026-08-01 00:38 UTCEG score recompute
  25. 2026-07-26 11:41 UTCEG score recompute
  26. 2026-07-23 03:19 UTCEG score recompute
  27. 2026-07-14 20:56 UTCEG score recompute

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-53603?
CVE-2026-53603 is a high-severity vulnerability; its CVE record was 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 the CVE record for CVE-2026-53603 published?
The CVE record for CVE-2026-53603 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 8, 2026; the record at its source may have been updated since.
Is CVE-2026-53603 actively exploited?
CVE-2026-53603 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (27th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-53603?
CVE-2026-53603 has a CVSS base score of 7.1 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-53603?
A fix for CVE-2026-53603 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-53603 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-53603

Explore →

Is Your Infrastructure Affected by CVE-2026-53603?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Book a Demo →Browse All CVEs