CVE-2025-21609: b3log Siyuan

Critical severity, CVSS 9.1. EPSS: 0.6% chance of exploitation in the next 30 days.

SiYuan is self-hosted, open source personal knowledge management software. SiYuan Note version 3.1.18 has an arbitrary file deletion vulnerability. The vulnerability exists in the `POST /api/history/getDocHistoryContent` endpoint. An attacker can craft a payload to exploit this vulnerability, resulting in the deletion of arbitrary files on the server. Commit d9887aeec1b27073bec66299a9a4181dc42969f3 fixes this vulnerability and is expected to be available in version 3.1.19.

Affected products

• b3log Siyuan: version 3.1.18 only

Published 2025-01-03. Last modified 2026-06-17.