Nil Pointer Dereference Vulnerability in SiYuan Product by SiYuan
CVE-2026-123492

6.9MEDIUM

Key Information:

Vendor

Siyuan-note

Status
Siyuan
Vendor
CVE Published:
6 November 2026

What is CVE-2026-123492?

The vulnerability in SiYuan before version 3.8.9 involves a nil pointer dereference within its privateCacheMiddleware. Authenticated attackers with a valid API token can exploit this flaw by sending a resources/read request in an active MCP session. This action can lead to a kernel panic, effectively crashing the kernel process and disrupting service availability.

Affected Version(s)

siyuan 0 < 3.8.9

siyuan 3.8.9

References

https://github.com/siyuan-note/siyuan/security/advisories...
vendor-advisory
https://www.vulncheck.com/advisories/siyuan-before-3.8.9-...
third-party-advisory

CVSS V4

Score:
6.9
Severity:
MEDIUM
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

Credit

xy3xy3
.