CVE-2026-85581: SiYuan before v3.8.2 Denial of Service via unauthenticated UI-process registration

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-04 · updated 2026-09-10
Weakness: CWE-770

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.

Affected products

siyuan-note siyuan: before 3.8.2 — fixed in 3.8.2

How to fix

Upgrade to a fixed version: siyuan-note siyuan 3.8.2. Check the vendor advisory for mitigations.

References

https://github.com/siyuan-note/siyuan/security/advisories/GHSA-wv96-wmf5-xvj2
https://www.vulncheck.com/advisories/siyuan-before-3.8.2-denial-of-service-via-unauthenticated-ui-process-registration

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