Vulnerability · Published Mar 3, 2026 · Assigned by GitHub_M
CVE-2026-21866Dify - Stored XSS in chat
Medium 5.1
In plain English
A medium-severity cross-site scripting in dify from langgenius. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 17% of all known vulnerabilities).
Severity (CVSS 4.0)5.1Medium
Exploit odds (30 days)0.3%top 83.2% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known
Official description
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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| langgenius | dify | < 1.11.2 |
Weakness: CWE-79 · 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
References
- https://github.com/langgenius/dify/security/advisories/GHSA-qpv6-75c2-75h4 x_refsource_CONFIRM
- https://github.com/langgenius/dify/pull/29811 x_refsource_MISC
- https://github.com/langgenius/dify/commit/ae17537470bba417a8971fff705dd82ecb043564 x_refsource_MISC