SiYuan before v3.8.4 does not validate the sender or restrict recipients in the 'siyuan-send-windows' IPC handler of the Electron main process (app/electron/main.js). The handler ignores event.sender and forwards any received payload to every BrowserWindow returned by BrowserWindow.getAllWindows(), including windows belonging to other opened workspaces. A renderer connected to an attacker-controlled remote kernel can therefore send {cmd: "lockscreenByMode"} and have it delivered across the workspace boundary; a sibling workspace window whose lockScreenMode is set to 1 invokes lockScreen(). Repeated messages allow the remote workspace to repeatedly lock unrelated local workspace windows, causing a limited denial of service. No confidentiality, integrity, or code-execution impact was observed.
CVE-2026-100634
“—” beside the score: it is equal to the CVSS score beside it.
Score 4.7 from GitHub Security Advisory published 2026-09-26. A secondary CVSS source baseline 4.7; sources differ by 0.0.
Also known asEUVD-2026-87728 (ENISA EUVD) · GHSA-w745-gjg3-r76m (GitHub Security Advisories)Source: ENISA EUVD
- CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
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).
- CVSS v3
- 4.7
- EG Score
- 4.7MEDIUMmedium confidence
- EG Risk
- 37EG Risk 37/100
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)Severity47% × 45%Impact severity (EG Severity): CVSS 4.7 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.Automatability0% × 15%CISA's SSVC Automatable value: no (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (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. - EPSS PROB
- 0.6%
- EPSS %ILE
- 46th
- 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 (4.7): severity, escalated by confirmed exploitation. This CVE's 4.7 is its impact severity (EG Severity), not escalated.
- EG Severity
- 4.7 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 0.6% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-25). 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 or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade 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. In the directive's words, “Fix on system upgrade” means that, “unless conditions change”, the vulnerability “should be remediated the next time the vulnerable asset receives a scheduled major upgrade or rebuild”: its timelines are “dynamic as facts change”, and a KEV listing shortens them.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 or medium mission impact; Track* at high (mission-essential systems).
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.
Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (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)60 days if the affected system is publicly exposed; Fix on system upgrade 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. In the directive's words, “Fix on system upgrade” means that, “unless conditions change”, the vulnerability “should be remediated the next time the vulnerable asset receives a scheduled major upgrade or rebuild”: its timelines are “dynamic as facts change”, and a KEV listing shortens them.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (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
September 26, 2026
Last Modified
October 8, 2026
Advisory Details (3)
Auto-updated Sep 26, 2026SiYuan before v3.8.4 Missing Authorization via siyuan-send-windows | Advisories | VulnCheck
https://www.vulncheck.com/advisories/siyuan-before-3.8.4-missing-authorization-via-siyuan-send-windowscommit 8641553a1f07 (siyuan-note/siyuan)
Fix landed in siyuan-note/siyuan commit 8641553a1f07 — awaiting tagged release
https://github.com/siyuan-note/siyuan/commit/8641553a1f07374001902d3ce773285db1292b2dUnrestricted siyuan-send-windows Broadcast Lacks Sender and Workspace Authorization · Advisory · siyuan-note/siyuan · GitHub
https://github.com/siyuan-note/siyuan/security/advisories/GHSA-wxp7-xpq8-8xpmVendor Advisories for CVE-2026-100634(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 9× in last 7d / 59× 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.
- 2026-11-01 16:33 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-31 16:31 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-30 16:33 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-29 16:32 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-28 16:31 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-26 16:30 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-26 15:33 UTCEG score recompute
- 2026-10-26 15:33 UTCGHSA enrichmentGHSA-w745-gjg3-r76m · GitHub CVSS 4.7
- 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-25 15:58 UTCEG score recompute
- 2026-10-24 16:31 UTCEPSS rescoreEPSS 0.5% · 39th percentile
- 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.5% · 39th percentile
- 2026-10-23 09:53 UTCEG score recompute
- 2026-10-23 09:53 UTCGHSA enrichmentGHSA-w745-gjg3-r76m · GitHub CVSS 4.7
- 2026-10-22 16:33 UTCEPSS rescoreEPSS 0.5% · 39th percentile
- 2026-10-21 16:31 UTCEPSS rescoreEPSS 0.5% · 39th percentile
- 2026-10-20 16:31 UTCEPSS rescoreEPSS 0.5% · 39th percentile
- 2026-10-19 16:31 UTCEPSS rescoreEPSS 0.5% · 39th percentile
- 2026-10-18 16:31 UTCEPSS rescoreEPSS 0.5% · 39th percentile
- 2026-10-18 05:11 UTCEG score recompute
- 2026-10-17 16:33 UTCEPSS rescoreEPSS 0.5% · 39th percentile
- 2026-10-16 16:40 UTCEPSS rescoreEPSS 0.5% · 39th percentile
- 2026-10-15 16:31 UTCEPSS rescoreEPSS 0.5% · 39th percentile
- 2026-10-14 16:31 UTCEPSS rescoreEPSS 0.5% · 39th percentile
Show 59 moreShow fewer
- 2026-10-13 16:33 UTCEPSS rescoreEPSS 0.5% · 38th percentile
- 2026-10-12 16:41 UTCEG score recompute
- 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.5% · 38th percentile
- 2026-10-11 20:16 UTCEG score recompute
- 2026-10-11 18:29 UTCEG score recompute
- 2026-10-11 13:51 UTCEG score recompute
- 2026-10-11 13:50 UTCGHSA enrichmentGHSA-w745-gjg3-r76m · GitHub CVSS 4.7
- 2026-10-11 13:47 UTCEPSS rescoreEPSS 0.5% · 38th percentile
- 2026-10-10 19:59 UTCEPSS rescoreEPSS 0.5% · 38th percentile
- 2026-10-10 14:29 UTCEG score recompute
- 2026-10-10 14:29 UTCGHSA enrichmentGHSA-w745-gjg3-r76m · GitHub CVSS 4.7
- 2026-10-09 20:06 UTCEPSS rescoreEPSS 0.5% · 38th percentile
- 2026-10-09 15:32 UTCEG score recompute
- 2026-10-09 15:32 UTCGHSA enrichmentGHSA-w745-gjg3-r76m · GitHub CVSS 4.7
- 2026-10-08 17:11 UTCEPSS rescoreEPSS 0.5% · 38th percentile
- 2026-10-08 16:33 UTCEG score recompute
- 2026-10-08 16:33 UTCGHSA enrichmentGHSA-w745-gjg3-r76m · GitHub CVSS 4.7
- 2026-10-08 16:02 UTCEG score recompute
- 2026-10-08 16:02 UTCGHSA enrichmentGHSA-w745-gjg3-r76m · GitHub CVSS 4.7
- 2026-10-08 05:25 UTCEG score recompute
- 2026-10-08 05:25 UTCGHSA enrichmentGHSA-w745-gjg3-r76m · GitHub CVSS 4.7
- 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.5% · 38th percentile
- 2026-10-07 06:27 UTCEG score recompute
- 2026-10-07 06:27 UTCGHSA enrichmentGHSA-w745-gjg3-r76m · GitHub CVSS 4.7
- 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.5% · 38th percentile
- 2026-10-06 07:29 UTCEG score recompute
- 2026-10-06 07:29 UTCGHSA enrichmentGHSA-w745-gjg3-r76m · GitHub CVSS 4.7
- 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.5% · 38th percentile
- 2026-10-05 08:32 UTCEG score recompute
- 2026-10-05 08:32 UTCGHSA enrichmentGHSA-w745-gjg3-r76m · GitHub CVSS 4.7
- 2026-10-04 23:21 UTCEPSS rescoreEPSS 0.5% · 38th percentile
- 2026-10-04 09:34 UTCEG score recompute
- 2026-10-04 09:34 UTCGHSA enrichmentGHSA-w745-gjg3-r76m · GitHub CVSS 4.7
- 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.5% · 38th percentile
- 2026-10-03 10:35 UTCEG score recompute
- 2026-10-03 10:35 UTCGHSA enrichmentGHSA-w745-gjg3-r76m · GitHub CVSS 4.7
- 2026-10-02 11:33 UTCEG score recompute
- 2026-10-02 11:32 UTCGHSA enrichmentGHSA-w745-gjg3-r76m · GitHub CVSS 4.7
- 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.5% · 38th percentile
- 2026-10-01 12:25 UTCEG score recompute
- 2026-10-01 12:25 UTCGHSA enrichmentGHSA-w745-gjg3-r76m · GitHub CVSS 4.7
- 2026-09-30 15:02 UTCEPSS rescoreEPSS 0.5% · 38th percentile
- 2026-09-30 13:24 UTCEG score recompute
- 2026-09-30 13:24 UTCGHSA enrichmentGHSA-w745-gjg3-r76m · GitHub CVSS 4.7
- 2026-09-30 13:13 UTCEG score recompute
- 2026-09-30 13:13 UTCGHSA enrichmentGHSA-w745-gjg3-r76m · GitHub CVSS 4.7
- 2026-09-30 10:28 UTCEG score recompute
- 2026-09-30 10:28 UTCGHSA enrichmentGHSA-w745-gjg3-r76m · GitHub CVSS 4.7
- 2026-09-29 15:20 UTCEPSS rescoreEPSS 0.5% · 38th percentile
- 2026-09-29 11:28 UTCEG score recompute
- 2026-09-29 11:28 UTCGHSA enrichmentGHSA-w745-gjg3-r76m · GitHub CVSS 4.7
- 2026-09-28 13:50 UTCEPSS rescoreEPSS 0.5% · 38th percentile
- 2026-09-28 12:30 UTCEG score recompute
- 2026-09-28 12:30 UTCGHSA enrichmentGHSA-w745-gjg3-r76m · GitHub CVSS 4.7
- 2026-09-27 13:32 UTCEG score recompute
- 2026-09-27 13:32 UTCGHSA enrichmentGHSA-w745-gjg3-r76m · GitHub CVSS 4.7
- 2026-09-26 14:34 UTCEG score recompute
- 2026-09-26 13:39 UTCEG score recomputeFirst assessed: 4.7 MEDIUM
- 2026-09-26 13:30 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(5)
What is CVE-2026-100634?
When was CVE-2026-100634 made public?
Is CVE-2026-100634 actively exploited?
What is the CVSS score of CVE-2026-100634?
How do I remediate CVE-2026-100634?
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-100634
Is Your Infrastructure Affected by CVE-2026-100634?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.