CVE-2026-53656

MEDIUMPre-NVD 6.36.3
EchelonGraph scoreLOW confidence

This medium-severity CVE scores 6.3 under the CNA's CVSS (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: cna:github_m
6.3
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: —CVSS: 6.3Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

FiftyOne App server uses wildcard CORS (Access-Control-Allow-Origin: *), enabling cross-origin reads of local server data

Impact

The FiftyOne App/API server (fiftyone/server/app.py) and the /media route (fiftyone/server/routes/media.py) unconditionally set a permissive CORS header (Access-Control-Allow-Origin: *) on their responses. Because the embedded App server runs locally and is unauthenticated, this allows any website a user visits to make cross-origin requests to that user's running FiftyOne server and read the responses.

Combined with the unauthenticated /media endpoint — which serves files from the local filesystem by path — the wildcard CORS policy turns a local-only file read into a remotely exploitable, drive-by data exfiltration vulnerability. A malicious web page can silently issue requests such as http://localhost:5151/media?filepath=/etc/passwd and read arbitrary files accessible to the server process (SSH keys, cloud credentials, .env files, dataset media, etc.), then exfiltrate them to an attacker-controlled endpoint.

The victim only needs to have a FiftyOne server running locally and visit a malicious page — no clicks or other interaction are required. Browsers that have shipped Private Network Access / local-network-access protections (e.g. Chromium 142+) mitigate this for some users, but Safari and Firefox do not yet, so the attack remains viable in common configurations.

Who is impacted: any user running FiftyOne (the open-source, embedded App server) locally while also browsing the web.

Not affected: media stored in cloud buckets, which is served via signed URLs on a separate origin.

Patches

Fixed in FiftyOne 1.17.0. The hard-coded Access-Control-Allow-Origin: * has been removed and the server now responds same-origin only by default, which covers local desktop usage and the supported notebook integrations (each served through a same-origin proxy or iframe).

Cross-origin access is now opt-in via a new allowed_origins config option (environment variable FIFTYONE_ALLOWED_ORIGINS), an explicit comma-separated list of trusted origins, e.g.:

export FIFTYONE_ALLOWED_ORIGINS='https://app.example.com,http://localhost:3000'

The literal value * restores the legacy wildcard behavior for users who explicitly require it and emits a warning.

Users should upgrade to FiftyOne 1.17.0 or later.

Workarounds

In affected versions there is no configuration flag to disable the wildcard CORS header without upgrading. Until you can upgrade:

  • Do not run the FiftyOne App server while browsing untrusted websites.
  • Keep the App server bound to localhost (the default) and avoid exposing it on a network interface.
  • Use a browser that enforces Private Network Access protections.

Resources

  • OWASP A01:2025 – Broken Access Control: https://owasp.org/Top10/2025/A01_2025-Broken_Access_Control/

CVSS v3
6.3
EG Score
6.3(low)
EPSS
—
KEV
Not listed

Published

July 15, 2026

Last Modified

July 15, 2026

Vendor Advisories for CVE-2026-53656(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Data Freshness Timeline

(refreshed 1× in last 7d / 1× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-15 22:19 UTCEG score recompute

Frequently asked(4)

What is CVE-2026-53656?
CVE-2026-53656 is a medium vulnerability published on July 15, 2026. FiftyOne App server uses wildcard CORS (Access-Control-Allow-Origin: *), enabling cross-origin reads of local server data Impact The FiftyOne App/API server (fiftyone/server/app.py) and the /media route (fiftyone/server/routes/media.py) unconditionally set a permissive CORS header…
When was CVE-2026-53656 disclosed?
CVE-2026-53656 was first published in the National Vulnerability Database on July 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
What is the CVSS score of CVE-2026-53656?
CVE-2026-53656 has a CVSS v4.0 base score of 6.3 (CNA self-assessment; NVD's own analysis pending). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-53656?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-53656, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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