CVE-2026-123492
SiYuan before 3.8.9 Nil Pointer Dereference DoS via MCP resources/read
CVSS Score
4.9
EPSS Score
0.0%
EPSS Percentile
0th
SiYuan before 3.8.9 contains a nil pointer dereference vulnerability in privateCacheMiddleware that allows authenticated attackers to crash the kernel by reading nonexistent MCP resources. Attackers with a valid API token can send a resources/read request in an initialized MCP session, causing a panic that terminates the kernel process and interrupts service.
| CWE | CWE-476 |
| Vendor | siyuan-note |
| Product | siyuan |
| Published | Nov 6, 2026 |
Stay Ahead of the Next One
Get instant alerts for siyuan-note siyuan
Be the first to know when new medium vulnerabilities affecting siyuan-note siyuan are published — delivered to Slack, Telegram or Discord.
Get Free Alerts →
Free · No credit card · 60 sec setup
CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H Attack Vector
Network
Attack Complexity
Low
Privileges Required
High
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Affected Versions
siyuan-note / siyuan
0 < 3.8.9
References
Credits
🔍 xy3xy3