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VulnerabilityPublished Updated

CVE-2026-100634: siyuan · Missing Authorization

Affects siyuanSource CVE Database V5

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Not known to be exploited · CVSS 5.3 Medium : upgrade to 3.8.4 when convenient.

Data as of 8 Nov 2026, 23:24 UTC

CVSS 4.0 base score
5.3Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.5% chance of exploitation in 30 days – higher than 46% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 3.8.4
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 26 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 9 Nov 2026.

What to do

Upgrade siyuan and siyuan-note/siyuan to 3.8.4.

Affected software

ProductAffectedFixed in
siyuan-notesiyuanAffected
  • <3.8.4
Fixed in
  • 3.8.4
GitHubsiyuan-note/siyuanpkg:github/siyuan-note/siyuanOther threatsAffected
  • <3.8.4
Fixed in
  • 3.8.4

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix is available in SiYuan version 3.8.4 and later. Users should upgrade to version 3.8.4 or newer to remediate this vulnerability. No other mitigation steps are indicated.

Description

SiYuan note-taking software versions before 3.8.4 contain a missing authorization vulnerability in the 'siyuan-send-windows' IPC handler within the Electron main process. This flaw allows a renderer connected to a remote kernel to send commands that cause windows from other workspaces to lock repeatedly, resulting in a limited denial of service. There is no observed impact on confidentiality, integrity, or code execution.

References

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