CVE-2026-49258

HIGHPre-NVD 8.88.8—
EchelonGraph scoreMEDIUM confidence

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2026-06-26. a secondary CVSS source baseline 8.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
8.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.8Exploit: 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 the Slack Nebula mesh VPN. In versions 0.3.5 and below, the web UI (/ui/*) does not apply the per-operator CA scoping employed by the JSON API. This was partially addressed by GHSA-598g-h2vc-h5vg, but the changes were not implemented in the web read/mutation surface. Any authenticated non-admin operator (for example, one created via self-registration or OIDC) can access resources belonging to other operators. The host create/edit/mobile-bundle/network-create paths and all CA-management routes were already correctly scoped. A malicious operator could block or delete any other operator's host, or read any operator's hosts and networks. This issue has been fixed in version 0.3.6.

CVSS v3
8.8
EG Score
8.8(medium)
EG Risk
40(Track)
EG Risk 40/100SSVC: 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
Severity88% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
21%
KEV
Not listed

Published

June 26, 2026

Last Modified

July 30, 2026

Advisory Details (2)

Auto-updated Jul 28, 2026
Patch available. Sources: github, github_pr.
github_pr

fix(web): unify host-ownership anchor on host.CAID across edit/update/mobile-bundle

Fix merged in forgekeep/nebula-mesh PR #161 on 2026-05-25 — awaiting tagged release

https://github.com/forgekeep/nebula-mesh/pull/161
github Patch Available

Web UI lacks ownership checks, enabling cross-operator access to hosts and networks (read, block, delete) · Advisory · forgekeep/nebula-mesh · GitHub

https://github.com/forgekeep/nebula-mesh/security/advisories/GHSA-c6v2-3ffm-vcmc

Vendor Advisories for CVE-2026-49258(1)

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

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
gogithub.com/juev/nebula-mesh—ghsa

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

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

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 26× in last 7d / 111× 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.

Showing the most recent 100 of 158 total refreshes for this CVE.

  1. 2026-08-23 07:54 UTCEG score recompute
  2. 2026-08-23 07:54 UTCGHSA enrichment
  3. 2026-08-23 00:19 UTCEPSS rescore
  4. 2026-08-22 21:00 UTCGHSA enrichment
  5. 2026-08-22 09:24 UTCEG score recompute
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  7. 2026-08-21 23:49 UTCEPSS rescore
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  17. 2026-08-18 23:41 UTCEG score recompute
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  21. 2026-08-17 14:53 UTCGHSA enrichment
  22. 2026-08-17 13:47 UTCEPSS rescore
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  24. 2026-08-16 17:04 UTCEG score recompute
  25. 2026-08-16 17:04 UTCGHSA enrichment
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  1. 2026-08-16 14:56 UTCEPSS rescore
  2. 2026-08-16 06:09 UTCEG score recompute
  3. 2026-08-16 06:09 UTCGHSA enrichment
  4. 2026-08-16 02:14 UTCEPSS rescore
  5. 2026-08-15 19:15 UTCGHSA enrichment
  6. 2026-08-15 08:20 UTCEG score recompute
  7. 2026-08-15 08:20 UTCGHSA enrichment
  8. 2026-08-15 01:30 UTCEPSS rescore
  9. 2026-08-14 21:25 UTCGHSA enrichment
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  11. 2026-08-13 23:36 UTCEG score recompute
  12. 2026-08-13 23:36 UTCGHSA enrichment
  13. 2026-08-13 22:00 UTCEPSS rescore
  14. 2026-08-13 12:39 UTCGHSA enrichment
  15. 2026-08-13 01:44 UTCGHSA enrichment
  16. 2026-08-12 14:50 UTCEG score recompute
  17. 2026-08-12 14:50 UTCGHSA enrichment
  18. 2026-08-12 13:51 UTCEPSS rescore
  19. 2026-08-12 03:56 UTCGHSA enrichment
  20. 2026-08-11 17:02 UTCEG score recompute
  21. 2026-08-11 17:02 UTCGHSA enrichment
  22. 2026-08-11 06:06 UTCEG score recompute
  23. 2026-08-11 06:06 UTCGHSA enrichment
  24. 2026-08-11 00:00 UTCEPSS rescore
  25. 2026-08-10 19:11 UTCGHSA enrichment
  26. 2026-08-10 08:17 UTCGHSA enrichment
  27. 2026-08-09 21:21 UTCEG score recompute
  28. 2026-08-09 21:21 UTCGHSA enrichment
  29. 2026-08-09 13:46 UTCEPSS rescore
  30. 2026-08-09 10:27 UTCGHSA enrichment
  31. 2026-08-08 23:33 UTCEG score recompute
  32. 2026-08-08 23:33 UTCGHSA enrichment
  33. 2026-08-08 16:37 UTCEPSS rescore
  34. 2026-08-08 12:38 UTCGHSA enrichment
  35. 2026-08-08 01:43 UTCEG score recompute
  36. 2026-08-08 01:43 UTCGHSA enrichment
  37. 2026-08-07 14:48 UTCGHSA enrichment
  38. 2026-08-07 03:53 UTCGHSA enrichment
  39. 2026-08-06 16:59 UTCEG score recompute
  40. 2026-08-06 16:59 UTCGHSA enrichment
  41. 2026-08-06 13:47 UTCEPSS rescore
  42. 2026-08-06 06:04 UTCEG score recompute
  43. 2026-08-06 06:04 UTCGHSA enrichment
  44. 2026-08-05 19:17 UTCEPSS rescore
  45. 2026-08-05 19:10 UTCGHSA enrichment
  46. 2026-08-05 08:16 UTCGHSA enrichment
  47. 2026-08-04 19:45 UTCEG score recompute
  48. 2026-08-04 19:45 UTCGHSA enrichment
  49. 2026-08-04 15:10 UTCEPSS rescore
  50. 2026-08-04 10:39 UTCEPSS rescore
  51. 2026-08-04 08:49 UTCGHSA enrichment
  52. 2026-08-03 19:36 UTCEG score recompute
  53. 2026-08-03 19:36 UTCGHSA enrichment
  54. 2026-08-03 10:36 UTCEPSS rescore
  55. 2026-08-03 08:41 UTCGHSA enrichment
  56. 2026-08-02 21:46 UTCGHSA enrichment
  57. 2026-08-02 10:52 UTCEG score recompute
  58. 2026-08-02 10:52 UTCGHSA enrichment
  59. 2026-08-02 02:27 UTCEPSS rescore
  60. 2026-08-01 23:57 UTCGHSA enrichment
  61. 2026-08-01 13:02 UTCEG score recompute
  62. 2026-08-01 13:02 UTCGHSA enrichment
  63. 2026-08-01 04:16 UTCEPSS rescore
  64. 2026-08-01 02:08 UTCGHSA enrichment
  65. 2026-07-31 14:38 UTCGHSA enrichment
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  67. 2026-07-30 16:47 UTCEG score recompute
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  71. 2026-07-30 11:11 UTCGHSA enrichment
  72. 2026-07-30 01:30 UTCEPSS rescore
  73. 2026-07-30 00:14 UTCGHSA enrichment
  74. 2026-07-29 08:48 UTCGHSA enrichment
  75. 2026-07-28 20:28 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-49258?
CVE-2026-49258 is a high vulnerability published on June 26, 2026. Nebula Mesh is a self-hosted control plane for the Slack Nebula mesh VPN. In versions 0.3.5 and below, the web UI (/ui/*) does not apply the per-operator CA scoping employed by the JSON API. This was partially addressed by GHSA-598g-h2vc-h5vg, but the changes were not implemented in the web…
When was CVE-2026-49258 disclosed?
CVE-2026-49258 was first published in the National Vulnerability Database on June 26, 2026, with the most recent update on July 30, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-49258 actively exploited?
CVE-2026-49258 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 79.1% of all scored CVEs.
What is the CVSS score of CVE-2026-49258?
CVE-2026-49258 has a CVSS v3 base score of 8.8 (NVD).
How do I remediate CVE-2026-49258?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-49258, 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.

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