CVE-2026-56395Public exploitNetwork attack vector

OS command execution via unsanitized Bazaar content

Published Jun 21, 2026 · Updated Jun 21, 2026

Stored XSS in SiYuan before 3.6.1 allows remote attackers to execute OS commands when a user browses a malicious Bazaar package. The Bazaar listing inserts displayName and description into HTML templates without escaping, while renderREADME preserves raw HTML and assigns it to innerHTML. Browsing a listing triggers metadata payloads; opening its README triggers that vector, and Electron nodeIntegration exposes child_process at the user's privileges.

CVSS severity9.4
Critical
EPSS probability0.70%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in SiYuan before 3.6.1 allows remote attackers to execute OS commands when a user browses a malicious Bazaar package. The Bazaar listing inserts displayName and description into HTML templates without escaping, while renderREADME preserves raw HTML and assigns it to innerHTML. Browsing a listing triggers metadata payloads; opening its README triggers that vector, and Electron nodeIntegration exposes child_process at the user's privileges.

The record

CVE
CVE-2026-56395
Published
Jun 21, 2026
Updated
Jun 21, 2026
Vendor
SiYuan Note
Product
SiYuan
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 21, 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 <3.6.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

SiYuan Note · SiYuanversion=0 <3.6.1

Published CVSS scores

9.6VulnCheckCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
9.4VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
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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