High severity · published Sep 4, 2026
CVE-2026-85581
SiYuan before v3.8.2 Denial of Service via unauthenticated UI-process registration
7.5
CVSS
0.6%
EPSS
No
On KEV
Description
SiYuan before v3.8.2 contains a denial of service vulnerability in the unauthenticated /api/system/uiproc endpoint that accepts and retains attacker-controlled process identifiers without size limits or authentication. Attackers can send repeated requests with unique identifiers to exhaust process memory and degrade service availability.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 47% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
SI
siyuan · siyuan-note
before 3.8.2 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-85581
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-85581
github.com
https://github.com/siyuan-note/siyuan/security/advisories/GHSA-wv96-wmf5-xvj2
www.vulncheck.com
https://www.vulncheck.com/advisories/siyuan-before-3.8.2-denial-of-service-via-unauthenticated-ui-process-registration
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