CVE-2026-21866

EUVD-2026-9325
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.
Cross-site Scripting
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
5.4 MEDIUM
NETWORK
LOW
LOW
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Affected Products (NVD)
VendorProductVersion
difydify
𝑥
< 1.11.2
𝑥
= Vulnerable software versions
Common Weakness Enumeration
References
https://github.com/langgenius/dify/commit/ae17537470bba417a8971fff705dd82ecb043564
https://github.com/langgenius/dify/pull/29811
https://github.com/langgenius/dify/security/advisories/GHSA-qpv6-75c2-75h4