Denial of Service Vulnerability in SiYuan by SiYuan Technology
CVE-2026-85581

8.7HIGH

Key Information:

Vendor

Siyuan-note

Status
Siyuan
Vendor
CVE Published:
4 September 2026

What is CVE-2026-85581?

SiYuan versions prior to 3.8.2 are vulnerable to a denial of service attack through the unauthenticated /api/system/uiproc endpoint. This endpoint improperly handling incoming requests allows attackers to control process identifiers without any size restrictions or authentication checks. By sending a barrage of requests with unique identifiers, an attacker can deplete memory resources, leading to degraded service performance and potential denial of access for legitimate users.

Affected Version(s)

siyuan 0 < 3.8.2

siyuan 3.8.2

References

https://github.com/siyuan-note/siyuan/security/advisories...
vendor-advisory
https://www.vulncheck.com/advisories/siyuan-before-3.8.2-...
third-party-advisory

CVSS V4

Score:
8.7
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.