Browser script execution via unsanitized chat content
Published Jun 20, 2026 · Updated Jun 20, 2026
Cross-site scripting in Flowise before 3.0.8 allows remote attackers to execute JavaScript in a victim's browser through crafted chat content. Chat message rendering and Agentflow Custom Function output accept iframe content with a javascript URL without neutralizing script-capable HTML. Execution requires a victim to view the affected chat or workflow, exposing cookies and session data to attacker-controlled code.
Summary
What happened
Cross-site scripting in Flowise before 3.0.8 allows remote attackers to execute JavaScript in a victim's browser through crafted chat content. Chat message rendering and Agentflow Custom Function output accept iframe content with a javascript URL without neutralizing script-capable HTML. Execution requires a victim to view the affected chat or workflow, exposing cookies and session data to attacker-controlled code.
The record
- CVE
- CVE-2025-71331
- Published
- Jun 20, 2026
- Updated
- Jun 20, 2026
- Vendor
- FlowiseAI
- Product
- Flowise
- Classifications
- CWE-80, T1203
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 20, 2026CVE publishedPublication date reported by the CVE source.
- Jun 20, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <3.0.8
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Flowise iframe javascript URL proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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