RCE in B3log Siyuan
CVE-2026-23852
SiYuan is a personal knowledge management system. Versions prior to 3.5.4 have a stored Cross-Site Scripting (XSS) vulnerability that allows an attacker to inject arbitrary HTML attributes into the `icon` attribute of a block via the `/api/attr/setBlockAttrs` API. The payload is later rendered in the dynamic icon feature in an unsanitized context, leading to stored XSS and, in the desktop environment, potential remote code execution (RCE). This issue bypasses the previous fix for issue `#15970` (XSS → RCE via dynamic icons). Version 3.5.4 contains an updated fix.
Vulnerability class: RCE (Remote Code Execution)
EPSS: 0.007 (48.6th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 9.6 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H.
Affected products
- B3log Siyuan
- Siyuan-note Siyuan — versions < 3.5.4
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Exploit, Patch, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-23852?
- CVE-2026-23852 is a critical-severity vulnerability in B3log Siyuan, classified under Code Injection. CVSS score: 9.6/10. Published 2026-01-19.
- How severe is CVE-2026-23852?
- Critical severity. CVSS v3 base score is 9.6 out of 10.