CVE-2026-74903

MEDIUMPre-NVD 4.34.3—
EchelonGraph scoreMEDIUM confidence

Score 4.3 from GitHub Security Advisory published 2026-08-18. A secondary CVSS source baseline 4.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this weekElevated
4.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 4.3Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

SiYuan before v3.7.4 contains an insufficient access control vulnerability in the /api/lute/spinBlockDOM endpoint, which is guarded only by CheckAuth middleware instead of CheckAdminRole like its sibling endpoint. Authenticated users with RoleEditor or RoleReader roles can invoke the endpoint to transform arbitrary DOM input, and large payloads cause endpoint starvation through per-path mutex serialization.

CVSS v3
4.3
EG Score
4.3MEDIUMmedium confidence
EG Risk
35
EG Risk 35/100CISA SSVC

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
Severity43% × 45%
Exploitation40% × 40%
Automatability0% × 15%
CISA SSVC: Track at low or medium mission impact; Track* at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.3%
EPSS %ILE
19th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 18, 2026

Last Modified

August 26, 2026

Advisory Details (2)

Auto-updated Aug 18, 2026
🔬 Proof of concept available. Patch available. Sources: github.
generic

SiYuan before v3.7.4 Insufficient Access Control via spinBlockDOM | Advisories | VulnCheck

https://www.vulncheck.com/advisories/siyuan-before-insufficient-access-control-via-spinblockdom
github Patch Available🟡 PoC Available

/api/lute/spinBlockDOM Accessible to All Authenticated Roles Without Admin Gate or Input Size Limit · Advisory · siyuan-note/siyuan · GitHub

https://github.com/siyuan-note/siyuan/security/advisories/GHSA-3j8q-5c8c-grwm

Vendor Advisories for CVE-2026-74903(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 14× in last 7d / 72× 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 128 total refreshes for this CVE.

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

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Frequently asked(5)

What is CVE-2026-74903?
CVE-2026-74903 is a medium vulnerability published on August 18, 2026. SiYuan before v3.7.4 contains an insufficient access control vulnerability in the /api/lute/spinBlockDOM endpoint, which is guarded only by CheckAuth middleware instead of CheckAdminRole like its sibling endpoint. Authenticated users with RoleEditor or RoleReader roles can invoke the endpoint to…
When was CVE-2026-74903 disclosed?
CVE-2026-74903 was first published on August 18, 2026, with the most recent update on August 26, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-74903 actively exploited?
CVE-2026-74903 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (19th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-74903?
CVE-2026-74903 has a CVSS base score of 4.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-74903?
A fix for CVE-2026-74903 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-74903 are linked in the Vendor Advisories panel on this page.

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