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CriticalVulnerabilityCVE-2026-83399updated 25 Oct 2026, 18:35 UTC

Oracle WebLogic Server can be fully taken over by unauthenticated network attackers

Attackers on the network can take control of the Oracle WebLogic Server without logging in. Anyone who runs this software should treat it as urgent.

Official, 2 sources
SeverityCriticalCVSS 9.8 of 10
Being exploited?UnclearNo reports either way yet
Fix available?UnclearNo fixed version published in the sources yet
How sure is this?Official, 2 sourcesBacked by an official source

How the attack works simplified

  1. 1Remote attackerNo login or credentials needed
  2. 2T3/IIOP requestSent over the network to the server
  3. 3WebLogic Core flawUnauthenticated request is accepted
  4. 4Server takeoverAttacker gains control of the server
  5. ResultAttacker controls the WebLogic server

What happened

An unauthenticated network-reachable flaw in the Core component of Oracle WebLogic Server (via the T3 and IIOP protocols) allows full compromise of the server, with CVSS 3.1 score 9.8.

Why it is dangerous: A successful attack can give the attacker complete control over the server, affecting confidentiality, integrity and availability. Any organization exposing WebLogic to a network is at risk.

Are you affected?

You are affected if you run Oracle WebLogic Server 12.2.1.4.0, 14.1.1.0.0, 14.1.2.0.0 or 15.1.1.0.0 with T3 or IIOP reachable over the network.

Oracle WebLogic Server (Oracle Fusion Middleware, Core component): 12.2.1.4.0, 14.1.1.0.0, 14.1.2.0.0, 15.1.1.0.0

What to do

  1. Check whether your WebLogic Server version is one of the affected releases
  2. Apply the security patch from Oracle's Critical Patch Update for the affected version
  3. Block T3 and IIOP traffic from untrusted networks until patched

Timeline

  1. 20 Oct 2026, 22:19 UTC
    Publicly disclosed
  2. 20 Oct 2026, 22:19 UTC
    Reported by NVD · NVD
  3. 25 Oct 2026, 18:35 UTC
    GitHub Advisory reported on it · GitHub Advisory

Sources 2 reports, oldest first

Official vendor, government CERT or advisory database

Technical details

ID
CVE-2026-83399 · GHSA-xphr-m446-69p7
CVSS
9.8 / 10
EPSS
0.5% chance of exploitation within 30 days
Disclosed
20 Oct 2026, 22:19 UTC
On Zero Radar
before the radar started
Last change
25 Oct 2026, 18:35 UTC

The plain-language parts and the attack diagram were written by an AI model (anthropic/claude-haiku-5.5) from the sources above. Facts like versions, exploitation and dates come from the sources themselves. How Zero Radar works

Oracle WebLogic Server can be fully taken over by unauthenticated network attackers · Zero Radar