GHSA-793v-589g-574v
Bokeh server applications have Incomplete Origin Validation in WebSockets
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
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Description
This vulnerability allows for Cross-Site WebSocket Hijacking (CSWSH) of a deployed Bokeh server instance.
Scope
This vulnerability is only relevant to deployed Bokeh server instances. There is no impact on static HTML output, standalone embedded plots, or Jupyter notebook usage.
This vulnerability does not prevent any requirements for up-front authentication on Bokeh servers that have authentication hooks in place, and cannot be used to make Bokeh servers deployed on private, internal networks accessible outside those networks.
Impact
If a Bokeh 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.
Patches
Patched in versions 3.8.2 and later.
Workarounds
None
Technical description
The match_host function in src/bokeh/server/util.py contains a flaw in how it compares hostnames against the allowlist patterns. The function uses Python's zip() function to iterate over the parts of the hostname and the pattern simultaneously. However, zip() stops iteration when the shortest iterable is exhausted.
Because the code only checks if the pattern is longer than the host (lines 232-233), but fails to check if the host is longer than the pattern, a host that starts with the pattern (but has additional segments) will successfully match.
For example, if the allowlist is configured to ['[example.com](http://example.com/)'], the function will incorrectly validate [example.com.bad.com](http://example.com.evil.com/) as a match:
hostparts:['example', 'com', 'bad', 'com']patternparts:['example', 'com']zipcomparesexample==example(OK) andcom==com(OK).- Iteration stops, and the function returns
True.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | bokeh | all versions | 3.8.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for bokeh. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update bokeh to 3.8.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-793v-589g-574v is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-793v-589g-574v is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-793v-589g-574v. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-793v-589g-574v in your dependencies?
O3 detects GHSA-793v-589g-574v across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.