CVE-2026-21866 MEDIUM

CVE-2026-21866: Dify - Stored XSS in chat

Vendor Langgenius
Product dify
Weakness CWE-79 · XSS
Published March 3, 2026
Last update March 4, 2026
View on NVD All CVEs

CVSS base score

5.1/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction —
Confidentiality —
Integrity —

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

What the vulnerability does

01Description

Dify is an open-source LLM app development platform. Prior to 1.11.2, Dify is vulnerable to a stored XSS issue when rendering Mermaid diagrams within chats. This occurs because Dify’s default Mermaid configuration uses securityLevel: loose, which allows potentially unsafe content to execute. This vulnerability is fixed in 1.11.2.

Key dates

02Disclosure timeline

March 3, 2026 CVE published
March 4, 2026 Record updated