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Oracle WebLogic Server EUVDEUVD-2026-106317

| CVE-2026-83399 CRITICAL
Improper Authentication (CWE-287)
2026-10-20 secalert_us@oracle.com GHSA-xphr-m446-69p7
9.8
CVSS 3.1 · Vendor: oracle
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Identify exposed T3/IIOP WebLogic port
  2. Exploit
    Send crafted T3/IIOP request to Core
  3. Execution
    Trigger unauthenticated compromise
  4. Impact
    Gain full server takeover

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A07:2025 - Authentication Failures
ASVS 5.0
V6 - Authentication Authentication mechanism validation
MITRE ATT&CK

2 techniques across 2 tactics: Defense Evasion, Initial Access

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

No special conditions beyond network reachability - remote unauthenticated exploitation against default configurations of Oracle WebLogic Server via the T3 or IIOP protocols. The practical limiting factor is network exposure of the T3/IIOP listener ports: environments that firewall, disable, or filter T3/IIOP (e.g., restrict these protocols to trusted management networks via connection filters) substantially reduce exposure. Affected builds are Oracle WebLogic Server 12.2.1.4.0, 14.1.1.0.0, 14.1.2.0.0, and 15.1.1.0.0; other versions are not listed as affected. No authentication, no user interaction, and no non-default feature enablement are required, which is why this ranks as critical.

Impact

This is a genuine top-priority vulnerability, not a high-CVSS-but-low-real-risk case. The CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N) describes the worst-case exposure profile: network-reachable, low attack complexity, no privileges, and no user interaction, with full C:H/I:H/A:H impact yielding complete server takeover. The description reinforces this independently, stating an unauthenticated attacker with network access via the T3 or IIOP protocols can compromise the server. The attack surface - Oracle WebLogic T3/IIOP - is historically one of the most heavily and reliably weaponized in enterprise software (prior WebLogic deserialization flaws have been routinely mass-exploited), which raises real-world concern even though exploitation-probability signals are absent here. No EPSS score was provided, the CVE is NOT listed in CISA KEV, and no public POC is referenced, so exploitation status must be stated as 'no public exploit identified at time of analysis.' The conflict to note explicitly: the input Tags label this 'Information Disclosure,' but both the CVSS impact (I:H/A:H, not confidentiality-only) and the description ('takeover') indicate full compromise - the tag understates the severity and should not be relied upon. Given WebLogic's internet exposure and exploitation history, this warrants emergency patching despite the lack of EPSS/KEV/POC data.

Exploit ScenarioDerived

An attacker locates an internet- or network-exposed WebLogic instance with the T3 or IIOP ports reachable (default on many deployments), then sends a crafted T3/IIOP request to the Core component that exploits the flaw without any authentication or user interaction. The single request results in complete takeover of the WebLogic Server. No public exploit code was identified in the provided data, but the AV:N/AC:L/PR:N/UI:N profile means a working exploit would be trivial to use at scale once developed.

Act Now Prioritize within 24-48h. Why: CRITICAL severity.
No patch listed yet 0.5% exploitation probability (EPSS)

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AnalysisAIv1 – Oct 21, 2026

Complete compromise of Oracle WebLogic Server is possible for unauthenticated, network-positioned attackers targeting the T3 or IIOP listeners in versions 12.2.1.4.0, 14.1.1.0.0, 14.1.2.0.0, and 15.1.1.0.0. The assessed CVSS 3.1 vector is AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H (9.8), meaning no credentials or user interaction are required and confidentiality, integrity, and availability are all fully impacted. No CISA KEV entry or public exploit code is identified in the provided intelligence at time of analysis, but the lack of exploit reporting does not reduce the priority for internet-exposed T3/IIOP endpoints.

RemediationAI

Apply the Oracle Critical Patch Update referenced at https://www.oracle.com/security-alerts/cpuoct2026.html; the provided data does not specify an exact fixed version, so confirm the applicable WebLogic Server patch level in My Oracle Support before deployment. Until patched, reduce exposure by restricting T3/IIOP to trusted networks with WebLogic connection filters or network firewalls, and disable IIOP if no CORBA/RMI-IIOP integrations depend on it-connection filters can break legitimate remote clients, and disabling IIOP will break IIOP-based integrations. Internet-facing T3/IIOP listeners should be treated as high priority for patching or immediate network isolation; no vendor workaround or public exploit code is identified in the supplied data.

Affected VersionsENISA

Oracle WebLogic Server 14.1.1.0.0
Oracle WebLogic Server 14.1.2.0.0
Oracle WebLogic Server 15.1.1.0.0
Oracle WebLogic Server 12.2.1.4.0

Affected Packages

euvd oracle_weblogic_server no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

Oracle WebLogic Server's Core component exposes the proprietary T3 remoting protocol and the IIOP/CORBA protocol; these listeners are the attack surface named in the Oracle advisory. The provided data does not include a CWE or a root-cause description, so the precise defect class-for example, unsafe object handling/deserialization versus another Core flaw-cannot be confirmed from the source material. The authoritative assessment treats it as remotely exploitable with no authentication, no user interaction, and no non-default feature requirement, which is consistent with a default-configuration WebLogic deployment where T3/IIOP is reachable. One supplied tag says 'Information Disclosure,' but that is inconsistent with the assessed C:H/I:H/A:H impact and Oracle's 'takeover' language; severity should follow the assessed vector. The main practical exposure control is whether T3/IIOP is reachable from untrusted networks.

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Severity by source

Vendor (oracle) PRIMARY 9.8 CRITICAL
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
vuln.today AI 9.8 CRITICAL

Unauthenticated remote exploitation over T3/IIOP with no user interaction (AV:N/AC:L/PR:N/UI:N) yielding full server takeover justifies C:H/I:H/A:H and unchanged scope.

3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (oracle).

CVSS VectorVendor: oracle

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

DescriptionCVE.org

Vulnerability in the Oracle WebLogic Server product of Oracle Fusion Middleware (component: Core). Supported versions that are affected are 12.2.1.4.0, 14.1.1.0.0, 14.1.2.0.0 and 15.1.1.0.0. Easily exploitable vulnerability allows unauthenticated attacker with network access via T3, IIOP to compromise Oracle WebLogic Server. Successful attacks of this vulnerability can result in takeover of Oracle WebLogic Server. CVSS 3.1 Base Score 9.8 (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:H).

Executive ViewAI

Why It Matters

Oracle WebLogic Server, a Java application platform that commonly fronts customer-facing and revenue-critical applications, is affected by a critical-severity flaw allowing an unauthenticated, network-positioned attacker to achieve complete compromise of confidentiality, integrity, and availability. Affected deployments in our estate would include versions 12.2.1.4.0, 14.1.1.0.0, 14.1.2.0.0, and 15.1.1.0.0, and no vendor-released patch is currently identified, leaving internet-reachable instances without a permanent fix. Leadership should care because no credentials or user interaction are required, and WebLogic instances typically host sensitive data and transaction paths that carry direct operational and regulatory exposure.

Business Impact: Severe
Compensating Controls

No vendor-released patch identified at time of analysis. Interim mitigations: restrict T3 and IIOP listener access using WebLogic connection filters (weblogic.security.net.ConnectionFilterImpl) limited to known-trusted hosts; disable the T3 protocol where not operationally required; block inbound T3/IIOP ports at the perimeter and segment affected servers from the internet and untrusted networks; enforce strong authentication and restricted network access on the Administration Console; monitor and alert on anomalous T3/IIOP traffic, unexpected deserialization payloads, and unusual outbound behavior from WebLogic hosts.

Threat Intelligence Overview

EPSS Score
0.5%
Top 57% exploitable
Prevalence
High
widely deployed enterprise Java application server across large organizations
Data Quality
4 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity CRITICAL
CISA KEV No
Public POC No
EPSS 0.5%
Patch available No
Active threat No
Deciding rule
CRITICAL severity
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
None
System Exposure· derived
Open
Automatable· derived
Yes
Human Impact
Very High

Priority Score

50
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +49
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

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