VulnerabilityAnalyzed

CVE-2026-23852

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.

MEDIUM 5.8EPSS 0.71%

Does this matter?

Lower severity and a low EPSS score (0.71%). Track it; it rarely justifies an emergency change on its own.

Description

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.

CVSS 4.0: 5.8 MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS: 0.71% probability · 51th percentile
CISA KEV: Not listed
Weakness: CWE-94, CWE-79
Affected: b3log/siyuan
Source: security-advisories@github.com

References

https://github.com/siyuan-note/siyuan/commit/0be7e1d4e0da9aac0da850b7aeb9b50ede7e5bdbPatch
https://github.com/siyuan-note/siyuan/security/advisories/GHSA-7c6g-g2hx-23vvExploit, Patch, Vendor Advisory

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.