Missing Origin Validation in WebSockets Affecting bokeh package, versions [,3.8.2)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-PYTHON-BOKEH-14894275
- published7 Jan 2026
- disclosed6 Jan 2026
- creditUnknown
Introduced: 6 Jan 2026
CVE-2026-21883 (opens in a new tab)How to fix?
Upgrade bokeh to version 3.8.2 or higher.
Overview
bokeh is an Interactive plots and applications in the browser from Python
Affected versions of this package are vulnerable to Missing Origin Validation in WebSockets via the match_host function in the server/util.py file. An attacker can gain unauthorized access to sensitive data or modify visualizations by exploiting flawed hostname validation logic in WebSocket connections.
Note: This is only exploitable if the server is deployed with an allowlist and the attacker can register a domain that starts with an allowed pattern.