XSS in Flowise
CVE-2025-71331
Flowise before 3.0.8 contains a cross-site scripting (XSS) vulnerability caused by insufficient input filtering in chat messages and custom agent functions. An attacker can inject malicious JavaScript by sending an iframe payload (e.g., <iframe src="javascript:alert(document.cookie)">) in a chat box, or by having a custom agent function return an XSS payload from an external website. The injected script executes in the victim's browser, enabling theft of cookies and session data.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (23.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 23rd percentile — 23.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000
Affected products
- Flowise — versions 0, 3.0.8
- Flowiseai Flowise
Weakness classification (CWE)
References
- github.com/FlowiseAI/Flowise/security/advisories/GHSA-4fr9-3x69-36wv (Exploit, vendor-advisory, Vendor Advisory)
- www.vulncheck.com/advisories/flowise-cross-site-scripting-in-chat-messages-and-… (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2025-71331?
- CVE-2025-71331 is a medium-severity vulnerability in Flowise, classified under Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS). CVSS score: 6.1/10. Published 2026-06-20.
- How severe is CVE-2025-71331?
- Medium severity. CVSS v3 base score is 6.1 out of 10.