CVE-2026-82654Public exploitNetwork attack vectorHinoki check available

Stored XSS via unescaped block metadata

Published Aug 30, 2026 · Updated Aug 30, 2026

Stored XSS in SiYuan before 3.8.1 allows remote authenticated users to execute script when another user views a referencing document. The genHintItemHTML function and backlink and breadcrumb renderers interpolate block name, alias, and memo values into HTML without escapeHtml encoding. An attacker needs permission to set block metadata, and a second user must display a hint, backlink, or breadcrumb; script then runs in that user's renderer.

CVSS severity9.3
Critical
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Stored XSS in SiYuan before 3.8.1 allows remote authenticated users to execute script when another user views a referencing document. The genHintItemHTML function and backlink and breadcrumb renderers interpolate block name, alias, and memo values into HTML without escapeHtml encoding. An attacker needs permission to set block metadata, and a second user must display a hint, backlink, or breadcrumb; script then runs in that user's renderer.

The record

CVE
CVE-2026-82654
Published
Aug 30, 2026
Updated
Aug 30, 2026
Vendor
SiYuan Note
Product
SiYuan
Classifications
CWE-79, CWE-116, T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 30, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 30, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <3.8.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

SiYuan Note · SiYuanversion=0 <3.8.1

Published CVSS scores

9.3VulnCheck CNACVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L
8.9VulnCheck CNACVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-116Improper Encoding or Escaping of Output
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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