CVE-2026-83105: Oracle Forms Auth Bypass Vulnerability

CVE-2026-83105 Overview

CVE-2026-83105 is an access control weakness [CWE-284] in the Oracle Forms component of Oracle Fusion Middleware. The flaw affects the Forms Services, C/S, Charmode subcomponent in supported versions 12.2.1.19.0 and 14.1.2.0.0. An unauthenticated attacker with network access over HTTP can compromise Oracle Forms and pivot to additional products due to a scope change. Successful exploitation results in full takeover of Oracle Forms, impacting confidentiality, integrity, and availability. Oracle addressed the issue in Security Alert CSPUSEP2026.

Critical Impact
Remote, unauthenticated attackers can take over Oracle Forms deployments and impact adjacent Fusion Middleware components through scope change.

Affected Products

Oracle Fusion Middleware - Oracle Forms 12.2.1.19.0
Oracle Fusion Middleware - Oracle Forms 14.1.2.0.0
Component: Forms Services, C/S, Charmode

Discovery Timeline

2026-09-15 - CVE-2026-83105 published to the National Vulnerability Database (NVD)
2026-09-17 - Last updated in NVD database

Technical Details for CVE-2026-83105

Vulnerability Analysis

The vulnerability resides in Oracle Forms Services when operating in client/server character mode (C/S, Charmode). The weakness is categorized as improper access control [CWE-284], meaning the component does not adequately restrict operations that should require authentication or authorization. An attacker communicating with the Forms Services endpoint over HTTP can send crafted requests that reach privileged functionality without presenting credentials.

Because the flaw triggers a scope change, code paths originating in Oracle Forms can influence resources managed by other Fusion Middleware components. This expands the blast radius beyond the Forms runtime itself. Oracle rates the exploitation as difficult, reflecting timing, configuration, or protocol conditions the attacker must satisfy before the request reaches the vulnerable handler.

Root Cause

The root cause is missing or insufficient access control enforcement in the Forms Services request-handling logic. Requests that should be gated by authentication or authorization checks are processed as if the caller were trusted. When paired with the client/server character mode handler, this allows an unauthenticated caller to perform actions that lead to full application takeover.

Attack Vector

Exploitation occurs over the network via HTTP against an exposed Oracle Forms Services endpoint. No user interaction and no prior authentication are required. Public technical details, proof-of-concept code, and exploit modules are not available at the time of publication. Refer to the Oracle Security Alert CSPUSEP2026 for vendor-supplied technical details.

No verified exploit code is publicly available. See the vendor advisory for authoritative technical details.

Detection Methods for CVE-2026-83105

Indicators of Compromise

Unexpected HTTP requests to Oracle Forms Services URIs, particularly those interacting with Forms Services, C/S, Charmode endpoints from untrusted networks.
Creation of new Oracle Forms application accounts, roles, or configuration changes outside approved change windows.
Unusual outbound connections or process spawning originating from the Oracle Forms server host.
Access to Fusion Middleware components from the Forms tier that does not correlate with legitimate business workflows.

Detection Strategies

Enable and review Oracle Forms and WebLogic access logs for anomalous request patterns, malformed URIs, and repeated failures preceding a successful request.
Baseline the process tree and network connections of the Forms Services host and alert on deviations such as new listening ports or child processes.
Correlate authentication events across Fusion Middleware to identify actions that occurred without a corresponding authenticated session.

Monitoring Recommendations

Forward Oracle Forms, WebLogic, and OS audit logs to a centralized SIEM for retention and correlation across the middleware stack.
Monitor the Oracle Security Alerts page for updated fix guidance and indicators.
Track EPSS movement for CVE-2026-83105 and prioritize hunts if exploitation likelihood increases.

How to Mitigate CVE-2026-83105

Immediate Actions Required

Inventory all Oracle Fusion Middleware deployments and identify hosts running Oracle Forms versions 12.2.1.19.0 and 14.1.2.0.0.
Apply the Oracle-supplied fix referenced in Security Alert CSPUSEP2026 as soon as change management allows.
Restrict network reachability of Oracle Forms Services endpoints to trusted management and application networks only.
Review recent access and audit logs on affected servers for signs of exploitation prior to patching.

Patch Information

Oracle has published fix guidance in the Oracle Security Alert CSPUSEP2026. Administrators should follow the alert to obtain the specific patch bundle applicable to their Fusion Middleware deployment and validate the fix in a non-production environment before rollout.

Workarounds

Place Oracle Forms Services behind an authenticated reverse proxy or web application firewall that terminates untrusted HTTP traffic.
Disable the C/S, Charmode functionality where it is not required by the business.
Enforce network segmentation so that the Forms tier cannot be reached directly from user or internet-facing networks.

bash

# Example: restrict access to Oracle Forms Services to a trusted management subnet
# Replace 10.10.20.0/24 with your trusted CIDR and eth0 with the appropriate interface
iptables -A INPUT -p tcp --dport 9001 -s 10.10.20.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 9001 -j DROP