CVE-2026-82654

9.3 criticalEPSS 0.4%

Critical (9.3). EPSS 0.4% chance of exploitation in the next 30 days.

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.

Severity

CVSS 4.0

9.3 critical

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

CVSS 3.1

8.9 high

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

EPSS: 0.4% chance of exploitation in the next 30 days; higher than 30% of CVEs (scores of 2026-10-31)
CWE: CWE-79
Published: 2026-08-30
Modified: 2026-09-01
Record from: the NVD, synced 2026-10-19

References

https://github.com/siyuan-note/siyuan/security/advisories/GHSA-hf87-qh3j-3p88
https://www.vulncheck.com/advisories/siyuan-before-3.8.1-stored-xss-via-block-name

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