CVE-2026-21883
Bokeh server applications have Incomplete Origin Validation in WebSockets
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.
INFO
Published Date :
Jan. 8, 2026, 2:15 a.m.
Last Modified :
Jan. 8, 2026, 6:08 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-21883
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update Bokeh to version 3.8.2 or newer.
- Review and reconfigure server allowlist settings.
- Validate server access controls carefully.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-21883.
| URL | Resource |
|---|---|
| https://github.com/bokeh/bokeh/commit/cedd113b0e271b439dce768671685cf5f861812e | |
| https://github.com/bokeh/bokeh/security/advisories/GHSA-793v-589g-574v |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-21883 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-21883
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-21883 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-21883 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Jan. 08, 2026
Action Type Old Value New Value Added 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. Added CVSS V4.0 AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-1385 Added Reference https://github.com/bokeh/bokeh/commit/cedd113b0e271b439dce768671685cf5f861812e Added Reference https://github.com/bokeh/bokeh/security/advisories/GHSA-793v-589g-574v