CVE-2026-25939 — fuxa-server
Fix: frangoteam/FUXA@5782b35CVE-2026-25939 is a CWE-862 vulnerability in fuxa-server. EPSS puts its 30-day exploitation probability at 11.7% (96th percentile). A fix is available for fuxa-server — see the affected versions and patch details below.
FUXA Unauthenticated Remote Arbitrary Scheduler Write
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
- 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-2026-25939.
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.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.
fuxa-servernpmDescription
Summary
An authorization bypass vulnerability in the FUXA allows an unauthenticated, remote attacker to create and modify arbitrary schedulers, exposing connected ICS/SCADA environments to follow-on actions. This vulnerability affects FUXA version 1.2.8 through version 1.2.10. This has been patched in FUXA version 1.2.11.
Impact
This affects all deployments, including those with runtime.settings.secureEnabled set to true.
Exploitation allows an unauthenticated, remote attacker to automatically authenticate as guest and create, modify or delete schedules. These schedules can be configured to trigger immediately or cyclically, forcing connected devices to specific states or values, or executing existing scripts on the server.
Patches
This issue has been patched in FUXA version 1.2.11. Users are strongly encouraged to update to the latest available release.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | fuxa-server | ≥ 1.2.8&&< 1.2.11 | 1.2.11npm install fuxa-server@1.2.11 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for fuxa-server, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update fuxa-server to 1.2.11 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-25939 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-25939 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-25939. 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-2026-25939 in your dependencies?
O3 Security finds CVE-2026-25939 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.