Python
CVE-2026-25516
MEDIUM
GHSA-v82v-c5x8-w282
Severity by source
AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Primary rating from GitHub Advisory · only source for this CVE.
CVSS VectorGitHub Advisory
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Lifecycle Timeline
4DescriptionGitHub Advisory
NiceGUI is a Python-based UI framework. The ui.markdown() component uses the markdown2 library to convert markdown content to HTML, which is then rendered via innerHTML. By default, markdown2 allows raw HTML to pass through unchanged. This means that if an application renders user-controlled content through ui.markdown(), an attacker can inject malicious HTML containing JavaScript event handlers. Unlike other NiceGUI components that render HTML (ui.html(), ui.chat_message(), ui.interactive_image()), the ui.markdown() component does not provide or require a sanitize parameter, leaving applications vulnerable to XSS attacks. This vulnerability is fixed in 3.7.0.
AnalysisAI
Cross-site scripting in NiceGUI's ui.markdown() component allows unauthenticated attackers to inject malicious HTML and JavaScript into applications that render user-controlled markdown content, as the component lacks built-in sanitization unlike other NiceGUI HTML rendering functions. Public exploit code exists for this vulnerability affecting NiceGUI versions before 3.7.0. …
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Vulnerability AssessmentAI
| Risk Assessment | CVSS 6.1 (MEDIUM). … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker could exploit this vulnerability to compromise the affected system. |
| Remediation | A vendor patch is available — apply it immediately. … Detailed patch versions, workarounds, and compensating controls in full report. |
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Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. …
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External POC / Exploit Code
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