CVE-2026-34448: b3log siyuan Cross-site Scripting

Vulnerability summary

CVE-2026-34448 is a critical (CVSS 9.1) Cross-site Scripting vulnerability in b3log siyuan. EPSS estimates a 0.73% chance of exploitation in the next 30 days, higher than 53.3% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 31-03-2026
   PublishedVulnerability first disclosed.
2. 03-04-2026
   Last modifiedVulnerability information updated.

Description

SiYuan is a personal knowledge management system. Prior to version 3.6.2, an attacker who can place a malicious URL in an Attribute View mAsse field can trigger stored XSS when a victim opens the Gallery or Kanban view with “Cover From -> Asset Field” enabled. The vulnerable code accepts arbitrary http(s) URLs without extensions as images, stores the attacker-controlled string in coverURL, and injects it directly into an <img src="..."> attribute without escaping. In the Electron desktop client, the injected JavaScript executes with nodeIntegration enabled and contextIsolation disabled, so the XSS reaches arbitrary OS command execution under the victim’s account. This issue has been patched in version 3.6.2.

• CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
• CWE-94Improper Control of Generation of Code ('Code Injection')The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.