Vulnerability in Oracle Helidon

CVE-2026-71166

Vulnerability in the Helidon product of Oracle Fusion Middleware (component: Imperative Web Server). Supported versions that are affected are 3.0.0-3.2.17. Easily exploitable vulnerability allows unauthenticated attacker with network access via HTTP to compromise Helidon. Successful attacks of this vulnerability can result in unauthorized creation, deletion or modification access to critical data or all Helidon accessible data as well as unauthorized access to critical data or complete access to all Helidon accessible data and unauthorized ability to cause a partial denial of service (partial DOS) of Helidon. CVSS 3.1 Base Score 9.4 (Confidentiality, Integrity and Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L).

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.4 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L.

EPSS exploit prediction

EPSS: 0.005 (37.3th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 37th percentile — 37.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-71166: held from 0.004 to 0.005.

EPSS over last 30 days · oldest: 0.004 · newest: 0.005 · change: +0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-71166?
CVE-2026-71166 is a critical-severity vulnerability in Oracle Helidon, classified under Improper Access Control. CVSS score: 9.4/10. Published 2026-08-18.
How severe is CVE-2026-71166?
Critical severity. CVSS v3 base score is 9.4 out of 10.