CVE-2026-25516

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{}

{"analysis": {"en": {"generated_at": "2026-04-17T22:23:43.503331+00:00", "value": {"mitigation_remediation": ["Upgrade NiceGUI to version 3.7.0 or later, which removes the raw\u2011HTML handling in ui.markdown().", "If an upgrade is not immediately possible, ensure that any user input sent to ui.markdown() is first sanitized to strip or encode raw HTML tags before rendering.", "Apply a restrictive Content Security Policy that disallows inline scripts and event handlers to mitigate the impact of any remaining XSS payloads."], "summary": {"action": "Patch", "impact": "Cross\u2011Site Scripting that allows arbitrary JavaScript execution"}, "threat_synthesis": {"affected_systems": "The flaw exists in all versions of the NiceGUI Python UI framework released before the 3.7.0 update. Any deployment that accepts or displays Markdown input via ui.markdown() is affected.", "description_and_impact": "NiceGUI\u2019s ui.markdown() component converts Markdown to HTML with markdown2, which permits raw HTML to pass through unchanged. When an application renders user\u2011controlled content via ui.markdown(), an attacker can embed malicious HTML containing JavaScript event handlers. The resulting vulnerability is a classic XSS flaw (CWE\u201179) that lets attackers execute arbitrary code in the victim\u2019s browser, potentially stealing data or hijacking sessions.", "risk_and_exploitability": "The CVSS score of 6.1 indicates a moderate severity. EPSS shows a probability of exploitation below 1\u202f%, suggesting attacks are not yet common, and the vulnerability is not listed in the CISA KEV catalog. Attackers can exploit this vector by providing malicious Markdown content through any user\u2011input channel that the application forwards to ui.markdown(). The described attack surface is inferred from the fact that user input is passed directly to the component; no additional privileges or network access are required."}}}}, "created": "2026-02-09T10:49:50.591155+00:00", "updated": "2026-04-17T22:30:29.593420+00:00", "vendors": ["zauberzeug", "zauberzeug$PRODUCT$nicegui"]}