CVE-2026-66012

CRITICALPre-NVD 10.010.0
EchelonGraph scoreMEDIUM confidence

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

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, GitHub Security Advisory, a secondary CVSS source
Trending — 3 sources updated this weekElevated

Also known asEUVD-2026-49043 (ENISA EUVD) · GHSA-hp8g-g2qj-wgpj (GitHub Security Advisories)Source: ENISA EUVD

10.0EG
EchelonGraph verdictPlan mitigationNo release containing the referenced fix is confirmed: check the referenced fix and the vendor's advisory for a release that contains it; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule 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: 0.8%CVSS: 10.0Exploit: No code on recordExposed services: Not assessed

A fix is referenced (a reference tagged "Patch", often a source commit), but no release containing it is confirmed — find the release that contains it; until it is applied, mitigate (WAF / firewall / segmentation).

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
10.0CRITICALmedium confidence
EG Risk
76
EG Risk 76/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity100% × 45%
Impact severity (EG Severity): CVSS 10.0 of 10. Never the KEV-floored or EPSS-lifted EG Score.
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, Track* at medium and Attend at high mission impact.
Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (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 referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule at low or medium mission impact and sooner than that at high.
EPSS PROB
0.8%
EPSS %ILE
55th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (10.0): severity, escalated by confirmed exploitation. This CVE's 10.0 is its impact severity (EG Severity), not escalated.

EG Severity
10.0 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.8% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-01). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track* at medium mission impactTrack at low, Track* at medium and Attend at high mission impact.CISA BOD 26-04: 3 days if the affected system is publicly exposed; 60 days if it is not.No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low, Track* at medium and Attend at high mission impact.

A fix is referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule at low or medium mission impact and sooner than that at high.

Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (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)3 days if the affected system is publicly exposed; 60 days if it is not.

No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact total (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 25, 2026

Last Modified

October 24, 2026

Advisory Details (3)

Auto-updated Nov 1, 2026
🔬 Proof of concept available. Fix referenced — no release confirmed yet. Sources: github_commit, github.
GitHub advisoryMentions a patch (unverified)🟡 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
Web page

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 21× in last 7d / 83× 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.

Showing the most recent 100 of 483 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 383 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-02 16:45 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  2. 2026-11-02 00:58 UTCEG score recompute
  3. 2026-11-02 00:58 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  4. 2026-11-01 03:04 UTCEG score recompute
  5. 2026-11-01 03:04 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  6. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  7. 2026-10-31 05:11 UTCEG score recompute
  8. 2026-10-31 05:10 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  9. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  10. 2026-10-30 07:16 UTCEG score recompute
  11. 2026-10-30 07:16 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  12. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  13. 2026-10-29 09:22 UTCEG score recompute
  14. 2026-10-29 09:22 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  15. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  16. 2026-10-28 11:29 UTCEG score recompute
  17. 2026-10-28 11:29 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  18. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  19. 2026-10-27 13:06 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  20. 2026-10-27 08:48 UTCEG score recompute
  21. 2026-10-27 08:48 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  22. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  23. 2026-10-26 09:14 UTCEG score recompute
  24. 2026-10-26 09:14 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  25. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.8% · 55th percentile
Show 75 more
  1. 2026-10-25 14:11 UTCEG score recompute
  2. 2026-10-25 11:20 UTCEG score recompute
  3. 2026-10-25 11:20 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  4. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  5. 2026-10-24 13:26 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  6. 2026-10-23 21:07 UTCEG score recompute
  7. 2026-10-23 21:07 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  8. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  9. 2026-10-22 23:12 UTCEG score recompute
  10. 2026-10-22 23:12 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  11. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  12. 2026-10-22 01:17 UTCEG score recompute
  13. 2026-10-22 01:17 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  14. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  15. 2026-10-21 03:20 UTCEG score recompute
  16. 2026-10-21 03:20 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  17. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  18. 2026-10-20 05:23 UTCEG score recompute
  19. 2026-10-20 05:23 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  20. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  21. 2026-10-19 06:45 UTCEG score recompute
  22. 2026-10-19 06:45 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  23. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  24. 2026-10-18 08:47 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  25. 2026-10-18 03:21 UTCEG score recompute
  26. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  27. 2026-10-17 06:11 UTCEG score recompute
  28. 2026-10-17 06:11 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  29. 2026-10-16 16:43 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  30. 2026-10-16 07:17 UTCEG score recompute
  31. 2026-10-16 07:17 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  32. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  33. 2026-10-15 06:12 UTCEG score recompute
  34. 2026-10-15 06:12 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  35. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  36. 2026-10-14 01:48 UTCEG score recompute
  37. 2026-10-14 01:48 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  38. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  39. 2026-10-12 22:01 UTCEG score recompute
  40. 2026-10-12 22:00 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  41. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  42. 2026-10-12 15:46 UTCEG score recompute
  43. 2026-10-12 06:03 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  44. 2026-10-11 19:31 UTCEG score recompute
  45. 2026-10-11 16:46 UTCEG score recompute
  46. 2026-10-11 14:07 UTCEG score recompute
  47. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  48. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  49. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  50. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  51. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  52. 2026-10-07 04:19 UTCEG score recompute
  53. 2026-10-07 04:19 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  54. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  55. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  56. 2026-10-04 12:39 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  57. 2026-10-04 07:24 UTCEG score recompute
  58. 2026-10-04 07:24 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  59. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  60. 2026-10-03 03:14 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  61. 2026-10-02 18:31 UTCEG score recompute
  62. 2026-10-02 18:31 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  63. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  64. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  65. 2026-10-01 16:11 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  66. 2026-10-01 12:13 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  67. 2026-10-01 07:54 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  68. 2026-10-01 03:57 UTCEG score recompute
  69. 2026-10-01 03:57 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  70. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  71. 2026-09-29 07:58 UTCEG score recompute
  72. 2026-09-29 07:58 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  73. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  74. 2026-09-28 12:58 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0
  75. 2026-09-28 08:12 UTCGHSA enrichmentGHSA-hp8g-g2qj-wgpj · GitHub severity CRITICAL · GitHub CVSS 10.0

Frequently asked(5)

What is CVE-2026-66012?
CVE-2026-66012 is a critical-severity vulnerability; its CVE record was 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 made public?
CVE-2026-66012 was made public on July 13, 2026: that is the date its CVE record's CNA, VulnCheck, gives for when the vulnerability was made public. The CVE record itself was published on July 25, 2026. EchelonGraph's copy of the record carries a last-modified date of October 24, 2026; the record at its source may have been updated since.
Is CVE-2026-66012 actively exploited?
CVE-2026-66012 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.8% probability of exploitation in the next 30 days (55th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-66012?
CVE-2026-66012 has a CVSS base score of 10.0 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-66012?
A fix for CVE-2026-66012 is referenced (a reference tagged "Patch", often a source commit), but EchelonGraph has no release containing it on record. Check that reference and the vendor's advisory for a release that contains the fix and update to it; until then, restrict network exposure of the affected system or apply the vendor's mitigation. The vendor advisories EchelonGraph has for CVE-2026-66012 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-66012

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