CVE-2026-82654

critical

Description

SiYuan before v3.8.1 fails to properly escape block name, alias, and memo fields in hint, backlink, and breadcrumb rendering functions. Attackers can set a block's name to contain HTML/script tags that execute when another user views documents referencing or displaying that block.

References

https://www.vulncheck.com/advisories/siyuan-before-3.8.1-stored-xss-via-block-name

https://github.com/siyuan-note/siyuan/security/advisories/GHSA-hf87-qh3j-3p88

Details

Source: Mitre, NVD

Published: 2026-08-30

Updated: 2026-08-31

Risk Information

CVSS v2

Base Score: 8.7

Vector: CVSS2#AV:N/AC:L/Au:S/C:C/I:C/A:P

Severity: High

CVSS v3

Base Score: 8.9

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:L

Severity: High

CVSS v4

Base Score: 9.3

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L

Severity: Critical

EPSS

EPSS: 0.00223