CVE-2026-73041Public exploitNetwork attack vector

Code execution via unescaped PDF annotation attributes

Published Aug 15, 2026 · Updated Aug 15, 2026

Stored cross-site scripting in SiYuan before 3.7.4 allows attackers to execute operating-system commands through malicious PDF annotations. The setFileAnnotation endpoint persists an opaque client string, and showHighlight inserts five unescaped fields into HTML attributes with insertAdjacentHTML. Execution requires a user to open a shared, imported, or synchronized PDF; the Electron renderer exposes Node.js child-process APIs at that user's privileges.

CVSS severity9.4
Critical
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored cross-site scripting in SiYuan before 3.7.4 allows attackers to execute operating-system commands through malicious PDF annotations. The setFileAnnotation endpoint persists an opaque client string, and showHighlight inserts five unescaped fields into HTML attributes with insertAdjacentHTML. Execution requires a user to open a shared, imported, or synchronized PDF; the Electron renderer exposes Node.js child-process APIs at that user's privileges.

The record

CVE
CVE-2026-73041
Published
Aug 15, 2026
Updated
Aug 15, 2026
Vendor
SiYuan Note
Product
SiYuan
Classifications
CWE-79, T1203, T1204.002
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 15, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=0 <3.7.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

SiYuan Note · SiYuanversion=0 <3.7.4

Published CVSS scores

9.0VulnCheckCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
9.4VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution
T1204.002User Execution Malicious File

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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