Is there a patch available for CVE-2026-42138?

Yes, a patch is available for CVE-2026-42138. Update the affected software to the latest version immediately.

Dify CVE-2026-42138

Q: What is the CVSS score of CVE-2026-42138?

CVE-2026-42138 has a CVSS 4.0 base score of 6.9 (Medium). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.1%.

EUVD-2026-27071 MEDIUM

Cross-site Scripting (XSS) (CWE-79)

2026-05-04 GitHub_M

XSS Dify

6.9

CVSS 4.0 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

6.9 MEDIUM

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Lifecycle Timeline

Analysis Generated

May 04, 2026 - 20:30 vuln.today

Patch available

May 04, 2026 - 19:17 EUVD

CVSS changed

May 04, 2026 - 18:22 NVD

6.9 (MEDIUM)

CVE Published

May 04, 2026 - 17:34 nvd

MEDIUM 6.9

DescriptionGitHub Advisory

Dify is an open-source LLM app development platform. Prior to version 1.13.1, using the method POST /api/files/upload, any unauthenticated user can upload an SVG file with XSS. The method POST /v1/files/upload, which requires authentication through the application API, is also vulnerable. This issue has been patched in version 1.13.1.

AnalysisAI

Unauthenticated users can upload SVG files containing XSS payloads via POST /api/files/upload in Dify prior to version 1.13.1, allowing cross-site scripting attacks against application users. The authenticated endpoint POST /v1/files/upload is similarly vulnerable. This vulnerability enables attackers to execute arbitrary JavaScript in the context of victim browsers, potentially compromising user sessions or stealing sensitive data without requiring any authentication or user interaction.

Technical ContextAI

Dify is an open-source large language model (LLM) application development platform that handles file uploads through HTTP endpoints. The vulnerability stems from improper validation and sanitization of uploaded SVG files, which are XML-based vector graphics that support embedded JavaScript through event handlers and script tags. The application fails to strip or neutralize XSS payloads in SVG uploads before they are served to users. SVG files are particularly dangerous in XSS contexts because they bypass many traditional image-only file validation checks. CWE-79 (Improper Neutralization of Input During Web Page Generation) indicates the root cause is insufficient input validation and output encoding of user-supplied content in web responses.

RemediationAI

Upgrade Dify to version 1.13.1 or later, which contains the vendor-released patch. For deployments unable to immediately upgrade, implement strict Content-Security-Policy (CSP) headers with script-src 'none' and object-src 'none' to prevent inline script execution, though this may affect functionality. Additionally, configure web server restrictions to reject SVG file uploads entirely if SVG support is not required for the application, or implement server-side SVG sanitization using a library like DOMPurify (Node.js) before serving uploaded SVG files to users. Disable the POST /api/files/upload unauthenticated endpoint if possible, requiring authentication for all file uploads, which reduces but does not eliminate risk if the authenticated endpoint is similarly exploited. Monitor logs for suspicious SVG uploads containing JavaScript patterns (event handlers, script tags, data URIs).