CVE-2026-100640

MEDIUMPre-NVD 4.74.7—
EchelonGraph scoreHIGH confidence

Score 4.7 from GitHub Security Advisory (severity: HIGH) published 2026-09-26. A secondary CVSS source baseline 4.7; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this weekElevated
4.7EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 4.7Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

SiYuan before v3.8.4 contains an authorization omission in the siyuan-get IPC handler that allows remote-kernel renderers to access native clipboard formats by invoking clipboardReadMathML, clipboardReadOffice, and clipboardReadWPS commands with matching plaintext. Attackers controlling remote renderer content can obtain MathML formulas, Office bytes, and WPS bytes from local clipboard during user-mediated paste operations.

CVSS v3
4.7
EG Score
4.7MEDIUMhigh confidence
EG Risk
37
EG Risk 37/100CISA 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
Severity47% × 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
0.2%
EPSS %ILE
7th
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

September 26, 2026

Last Modified

September 28, 2026

Advisory Details (2)

Auto-updated Sep 26, 2026
🔬 Proof of concept available. Patch available. Sources: github.
generic

SiYuan before v3.8.4 Clipboard Data Disclosure via IPC | Advisories | VulnCheck

https://www.vulncheck.com/advisories/siyuan-before-3.8.4-clipboard-data-disclosure-via-ipc
github Patch Available🟡 PoC Available

Remote-kernel Electron IPC exposes native clipboard contents to a remote window · Advisory · siyuan-note/siyuan · GitHub

Affected: v3.8.2 and concerns forged web clipboard formats reaching an unsafe local paste/r

https://github.com/siyuan-note/siyuan/security/advisories/GHSA-mjmm-hgmc-m7qf

Vendor Advisories for CVE-2026-100640(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 23× in last 7d / 26× 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.

  1. 2026-10-03 23:21 UTCEG score recompute
  2. 2026-10-03 23:21 UTCGHSA enrichment
  3. 2026-10-03 14:25 UTCEPSS rescore
  4. 2026-10-02 22:13 UTCEG score recompute
  5. 2026-10-02 22:13 UTCGHSA enrichment
  6. 2026-10-01 21:06 UTCEG score recompute
  7. 2026-10-01 21:06 UTCGHSA enrichment
  8. 2026-10-01 19:49 UTCEPSS rescore
  9. 2026-09-30 19:59 UTCEG score recompute
  10. 2026-09-30 19:59 UTCGHSA enrichment
  11. 2026-09-30 15:02 UTCEPSS rescore
  12. 2026-09-29 18:52 UTCEG score recompute
  13. 2026-09-29 18:52 UTCGHSA enrichment
  14. 2026-09-29 15:20 UTCEPSS rescore
  15. 2026-09-28 17:43 UTCEG score recompute
  16. 2026-09-28 17:42 UTCGHSA enrichment
  17. 2026-09-28 17:03 UTCEG score recompute
  18. 2026-09-28 17:03 UTCGHSA enrichment
  19. 2026-09-28 16:49 UTCEG score recompute
  20. 2026-09-28 16:49 UTCGHSA enrichment
  21. 2026-09-28 13:50 UTCEPSS rescore
  22. 2026-09-27 15:42 UTCEG score recompute
  23. 2026-09-27 15:41 UTCGHSA enrichment
  24. 2026-09-26 14:34 UTCEG score recompute
  25. 2026-09-26 13:40 UTCEG score recompute
Show 1 more
  1. 2026-09-26 13:30 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-100640?
CVE-2026-100640 is a medium vulnerability published on September 26, 2026. SiYuan before v3.8.4 contains an authorization omission in the siyuan-get IPC handler that allows remote-kernel renderers to access native clipboard formats by invoking clipboardReadMathML, clipboardReadOffice, and clipboardReadWPS commands with matching plaintext. Attackers controlling remote…
When was CVE-2026-100640 disclosed?
CVE-2026-100640 was first published on September 26, 2026, with the most recent update on September 28, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-100640 actively exploited?
CVE-2026-100640 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (7th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-100640?
CVE-2026-100640 has a CVSS base score of 4.7 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-100640?
A fix for CVE-2026-100640 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-100640 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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