CVE-2026-66012

CRITICALPre-NVD 10.010.0—
EchelonGraph scoreMEDIUM confidence

Score 10.0 from GitHub Security Advisory (severity: CRITICAL) published 2026-07-25. a secondary CVSS source baseline 10.0; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this weekElevated
10.0EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 10.0Exploit: Elevated riskExposed: 0

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

SiYuan before v3.7.2 contains a missing authorization vulnerability in the POST /mcp kernel endpoint, which is gated only by a general auth check (model.CheckAuth) with no admin-role or read-only enforcement. This exposes 31 MCP tools, including a file tool with list/read/write/delete/rename/copy actions across the entire workspace. When the Publish server is enabled in anonymous mode (Conf.Publish.Enable=true and Conf.Publish.Auth.Enable=false), the Publish reverse proxy attaches an anonymous RoleReader JWT to proxied requests, allowing a remote unauthenticated attacker to reach /mcp. The attacker can read conf/conf.json to extract accessAuthCode, api.token, and cookieKey in plaintext, write arbitrary files in the workspace, and plant a plugin into data/plugins/ that executes with nodeIntegration:true and no contextIsolation on the next desktop launch, leading to administrator takeover.

CVSS v3
10.0
EG Score
10.0(medium)
EG Risk
76(Attend)
EG Risk 76/100SSVC: 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
Severity100% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
1%
EPSS %ILE
45%
KEV
Not listed

Published

July 25, 2026

Last Modified

July 28, 2026

Advisory Details (3)

Auto-updated Sep 15, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github.
github Patch Available🟡 PoC Available

Unauthenticated Administrator takeover exfiltrated via the MCP · Advisory · siyuan-note/siyuan · GitHub

https://github.com/siyuan-note/siyuan/security/advisories/GHSA-cvhv-7xhj-xjp8
generic

SiYuan before v3.7.2 Unauthenticated Administrator Takeover via MCP | Advisories | VulnCheck

https://www.vulncheck.com/advisories/siyuan-before-unauthenticated-administrator-takeover-via-mcp
github_commit

commit c72ca4cd0901 (siyuan-note/siyuan)

Fix landed in siyuan-note/siyuan commit c72ca4cd0901 — awaiting tagged release

https://github.com/siyuan-note/siyuan/commit/c72ca4cd09019e5f64afdee8f8c6ec5ef34858db

Vendor Advisories for CVE-2026-66012(1)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 34× in last 7d / 158× 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 342 total refreshes for this CVE.

  1. 2026-09-15 09:18 UTCEG score recompute
  2. 2026-09-15 09:18 UTCGHSA enrichment
  3. 2026-09-14 15:51 UTCGHSA enrichment
  4. 2026-09-14 09:17 UTCGHSA enrichment
  5. 2026-09-14 05:18 UTCGHSA enrichment
  6. 2026-09-14 01:20 UTCGHSA enrichment
  7. 2026-09-13 21:22 UTCGHSA enrichment
  8. 2026-09-13 17:05 UTCEG score recompute
  9. 2026-09-13 17:05 UTCGHSA enrichment
  10. 2026-09-13 13:07 UTCGHSA enrichment
  11. 2026-09-13 09:09 UTCGHSA enrichment
  12. 2026-09-13 05:11 UTCGHSA enrichment
  13. 2026-09-13 01:13 UTCGHSA enrichment
  14. 2026-09-12 21:02 UTCGHSA enrichment
  15. 2026-09-12 17:04 UTCEG score recompute
  16. 2026-09-12 17:04 UTCGHSA enrichment
  17. 2026-09-12 13:06 UTCGHSA enrichment
  18. 2026-09-12 09:08 UTCGHSA enrichment
  19. 2026-09-12 04:55 UTCGHSA enrichment
  20. 2026-09-12 00:45 UTCGHSA enrichment
  21. 2026-09-11 20:27 UTCGHSA enrichment
  22. 2026-09-11 16:20 UTCEG score recompute
  23. 2026-09-11 16:20 UTCGHSA enrichment
  24. 2026-09-11 14:53 UTCEPSS rescore
  25. 2026-09-11 09:37 UTCEPSS rescore
Show 75 more
  1. 2026-09-11 07:09 UTCGHSA enrichment
  2. 2026-09-11 02:07 UTCGHSA enrichment
  3. 2026-09-10 20:51 UTCGHSA enrichment
  4. 2026-09-10 14:41 UTCGHSA enrichment
  5. 2026-09-10 10:24 UTCEG score recompute
  6. 2026-09-10 10:24 UTCGHSA enrichment
  7. 2026-09-09 12:29 UTCGHSA enrichment
  8. 2026-09-09 08:28 UTCEG score recompute
  9. 2026-09-09 08:28 UTCGHSA enrichment
  10. 2026-09-08 22:01 UTCEPSS rescore
  11. 2026-09-08 01:08 UTCGHSA enrichment
  12. 2026-09-07 21:10 UTCEG score recompute
  13. 2026-09-07 21:09 UTCGHSA enrichment
  14. 2026-09-07 16:01 UTCEPSS rescore
  15. 2026-09-06 23:59 UTCGHSA enrichment
  16. 2026-09-06 15:50 UTCEG score recompute
  17. 2026-09-06 15:50 UTCGHSA enrichment
  18. 2026-09-06 13:47 UTCEPSS rescore
  19. 2026-09-06 11:51 UTCGHSA enrichment
  20. 2026-09-06 07:53 UTCGHSA enrichment
  21. 2026-09-06 03:37 UTCGHSA enrichment
  22. 2026-09-05 23:16 UTCGHSA enrichment
  23. 2026-09-05 19:17 UTCEG score recompute
  24. 2026-09-05 19:17 UTCGHSA enrichment
  25. 2026-09-05 15:31 UTCEPSS rescore
  26. 2026-09-05 09:51 UTCGHSA enrichment
  27. 2026-09-05 05:53 UTCGHSA enrichment
  28. 2026-09-04 17:05 UTCEG score recompute
  29. 2026-09-04 17:05 UTCGHSA enrichment
  30. 2026-09-04 12:37 UTCEG score recompute
  31. 2026-09-04 12:37 UTCGHSA enrichment
  32. 2026-09-04 05:07 UTCEPSS rescore
  33. 2026-09-02 14:12 UTCEPSS rescore
  34. 2026-09-01 23:06 UTCEG score recompute
  35. 2026-09-01 23:06 UTCGHSA enrichment
  36. 2026-09-01 13:54 UTCEPSS rescore
  37. 2026-09-01 04:40 UTCEPSS rescore
  38. 2026-08-31 07:52 UTCGHSA enrichment
  39. 2026-08-31 03:51 UTCGHSA enrichment
  40. 2026-08-30 23:52 UTCGHSA enrichment
  41. 2026-08-30 19:55 UTCEG score recompute
  42. 2026-08-30 19:55 UTCGHSA enrichment
  43. 2026-08-30 19:17 UTCEPSS rescore
  44. 2026-08-30 15:57 UTCGHSA enrichment
  45. 2026-08-30 11:59 UTCGHSA enrichment
  46. 2026-08-30 07:57 UTCGHSA enrichment
  47. 2026-08-30 03:57 UTCEG score recompute
  48. 2026-08-30 03:57 UTCGHSA enrichment
  49. 2026-08-30 01:22 UTCEPSS rescore
  50. 2026-08-29 23:59 UTCEG score recompute
  51. 2026-08-29 23:59 UTCGHSA enrichment
  52. 2026-08-28 21:42 UTCEPSS rescore
  53. 2026-08-28 01:28 UTCGHSA enrichment
  54. 2026-08-27 21:03 UTCEG score recompute
  55. 2026-08-27 21:03 UTCGHSA enrichment
  56. 2026-08-27 13:51 UTCGHSA enrichment
  57. 2026-08-27 09:53 UTCGHSA enrichment
  58. 2026-08-27 03:43 UTCGHSA enrichment
  59. 2026-08-26 23:46 UTCGHSA enrichment
  60. 2026-08-26 19:48 UTCEG score recompute
  61. 2026-08-26 19:47 UTCGHSA enrichment
  62. 2026-08-26 14:47 UTCEPSS rescore
  63. 2026-08-26 11:47 UTCGHSA enrichment
  64. 2026-08-26 07:48 UTCGHSA enrichment
  65. 2026-08-26 03:38 UTCGHSA enrichment
  66. 2026-08-25 23:39 UTCGHSA enrichment
  67. 2026-08-25 19:39 UTCGHSA enrichment
  68. 2026-08-25 15:37 UTCEG score recompute
  69. 2026-08-25 15:37 UTCGHSA enrichment
  70. 2026-08-25 13:49 UTCEPSS rescore
  71. 2026-08-25 11:38 UTCGHSA enrichment
  72. 2026-08-25 07:40 UTCGHSA enrichment
  73. 2026-08-25 03:43 UTCGHSA enrichment
  74. 2026-08-24 23:45 UTCGHSA enrichment
  75. 2026-08-24 19:46 UTCGHSA enrichment

Frequently asked(5)

What is CVE-2026-66012?
CVE-2026-66012 is a critical vulnerability published on July 25, 2026. SiYuan before v3.7.2 contains a missing authorization vulnerability in the POST /mcp kernel endpoint, which is gated only by a general auth check (model.CheckAuth) with no admin-role or read-only enforcement. This exposes 31 MCP tools, including a file tool with list/read/write/delete/rename/copy…
When was CVE-2026-66012 disclosed?
CVE-2026-66012 was first published in the National Vulnerability Database on July 25, 2026, with the most recent update on July 28, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-66012 actively exploited?
CVE-2026-66012 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 55.5% of all scored CVEs.
What is the CVSS score of CVE-2026-66012?
CVE-2026-66012 has a CVSS v3 base score of 10.0 (NVD).
How do I remediate CVE-2026-66012?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-66012, 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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