CVE-2026-21866CWE-79

Dify - Stored XSS in chat

Medium · published March 3, 2026

CVSS v4.0
5.1
EPSS
0%
Percentile
13.2
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
5.1 · MEDIUM
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
EPSS
0.00232 · 13.2th percentile
Weakness
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Published
2026-03-03T21:42Z
EPSS history
Timeline
  • 03 MAR 21:42Z
    Dify - Stored XSS in chat
    cvelistv5