CVE-2026-53656 is a medium-severity (CVSS 6.3) CWE-346 vulnerability in fiftyone. O3 Security confirms whether CVE-2026-53656 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
FiftyOne App server uses wildcard CORS (Access-Control-Allow-Origin: *), enabling cross-origin reads of local server data
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-53656.
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.
How urgent is this, really
CVE-2026-53656 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 369,023 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
fiftyoneReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
FiftyOne is an open-source platform for refining high-quality datasets and visual AI models. Prior to 1.17.0, the FiftyOne App/API server in fiftyone/server/app.py and the /media route in fiftyone/server/routes/media.py unconditionally return Access-Control-Allow-Origin: *. Because the embedded server is local and unauthenticated, a malicious website visited by the user can read cross-origin responses. The /media endpoint accepts a filesystem path, allowing a drive-by page to read files accessible to the server process and exfiltrate them without additional clicks. The allowed_origins configuration and FIFTYONE_ALLOWED_ORIGINS environment variable now make cross-origin access explicit, while the default policy is same-origin. This issue is fixed in version 1.17.0.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | fiftyone | all versions | 1.17.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for fiftyone. 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 fiftyone to 1.17.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-53656 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 CVE-2026-53656 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 CVE-2026-53656. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-53656 in your dependencies?
O3 detects CVE-2026-53656 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.