Bokeh server applications have Incomplete Origin Validation in WebSockets
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Active
- Attack complexity
- Low
- Attack requirements
- Present
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · None
- Fix status
- Partial Red Hat: 1 without a fix
Attack profile from CVSS 4.0 · CNA. Fix status from CNA, GitHub and Red Hat.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| bokeh | bokeh | before 3.8.2 | 3.8.2 | Patch available | CNA |
| — | bokeh (PyPI) | before 3.8.2 | 3.8.2 | Patch available | GHSA-793v-589g-574v |
- bokeh Vendorbokeh Affected before 3.8.2 Fixed in 3.8.2 Patch available CNA
- bokeh (PyPI) Vendor— Affected before 3.8.2 Fixed in 3.8.2 Patch available GHSA-793v-589g-574v
Remediation
- Fix · CNA bokeh (bokeh) Fixed in 3.8.2
- Fix · GHSA-793v-589g-574v bokeh (PyPI) Fixed in 3.8.2 Advisory →
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat OpenShift AI (RHOAI) | Affected | No fix yet: Fix deferred |
Timeline
- 2026-10-02 Threatist record created from CVE-2026-21883
- 2026-10-03 Alias added: GHSA-793v-589g-574v
References
Exploit 2
Sources
- CVE-2026-21883 · CVE Program
- CVE-2026-21883 · NVD
- FIRST EPSS
- GHSA-793v-589g-574v · GitHub Advisory Database · CC BY 4.0
- CVE-2026-21883 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences