CVE 4.5 MEDIUM

Bokeh server applications have Incomplete Origin Validation in WebSockets_CVE-2026-21883

4.5 / 10
MEDIUM
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U

Description

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.

Basic Information

ID CVE-2026-21883
Source GitHub_M
Published Jan 8, 2026 at 01:20

Affected Product

Vendor bokeh
Product bokeh
Version < 3.8.2
Affected Versions bokeh bokeh < 3.8.2

CWE Classification

References

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