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TI-2026-17568 Aliases CVE-2026-21866

Dify - Stored XSS in chat

Priority MEDIUM 56CWE-79Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
Passive
Attack complexity
Low
Attack requirements
None
Impact type
Cross-site scripting
Confidentiality · integrity · availability
None · None · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-79.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00252 16th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed dify (langgenius): 1.11.2

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
langgeniusdifybefore 1.11.21.11.2Patch availableCNA
  • dify Vendorlanggenius Affected before 1.11.2 Fixed in 1.11.2 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:dify:dify:*:*:*:*:*:*:*:*before 1.11.2VulnerableDify
  • cpe:2.3:a:dify:dify:*:*:*:*:*:*:*:* Versions before 1.11.2 Vulnerable ·Dify

Remediation

  • Fix · CNA dify (langgenius) Fixed in 1.11.2

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-21866

References

Exploit 1

Patch 2

  • TI-2025-35265 Default credentials in Dify thru 1.5.1. CVSS 3.1CRITICAL 9.8
  • TI-2026-30343 Dify < 1.14.2 Authorization Bypass via Trace Configuration Endpoints CVSS 4.0CRITICAL 9.3
  • TI-2026-68373 Unauthenticated server-side request forgery in Dify remote file upload CVSS 3.1HIGH 8.3
  • TI-2026-30344 Dify v1.14.1 Path Traversal via Plugin Daemon Internal API Access CVSS 4.0CRITICAL 9.3
  • TI-2026-44066 Dify < 1.16.0-rc1 SQL Injection via MyScale Vector Store search_by_full_text CVSS 4.0HIGH 8.7
  • TI-2025-03045 Unsanitized Input in langgenius/dify CVSS 3.1HIGH 7.2
See all 48 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences