Bug 2427763 (CVE-2026-21883)

Summary: CVE-2026-21883 Bokeh: Bokeh: Information disclosure and unauthorized actions via flawed WebSocket origin validation
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: jkoehler, lphiri
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Bokeh, an interactive visualization library. A remote attacker could exploit flawed origin validation logic in WebSocket connections, which are used for real-time communication between a web browser and a server. By luring a victim to a malicious website, the attacker could bypass the server's security checks, establish a connection, and interact with the Bokeh server on the victim's behalf. This could lead to unauthorized access to sensitive data or modification of visualizations.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-01-08 02:01:48 UTC 
Bokeh is an interactive visualization library written in Python. In versions 3.8.1 and below, if a server is configured with an allowlist (e.g., dashboard.corp), an attacker can register a domain like dashboard.corp.attacker.com (or use a subdomain if applicable) and lure a victim to visit it. The malicious site can then initiate a WebSocket connection to the vulnerable Bokeh server. Since the Origin header (e.g., http://dashboard.corp.attacker.com/) matches the allowlist according to the flawed logic, the connection is accepted. Once connected, the attacker can interact with the Bokeh server on behalf of the victim, potentially accessing sensitive data, or modifying visualizations. This issue is fixed in version 3.8.2.