CVE-2026-83445

Executive Summary

CVE-2026-83445 is a high-severity vulnerability (CVSS 3.1 Base Score 8.8) in the Internal Operations component of Oracle Complex Maintenance, Repair and Overhaul (CMRO), a module within Oracle E-Business Suite. Supported versions 12.2.3 through 12.2.15 are affected, and a low-privileged attacker with network access via HTTPS can exploit it to achieve full takeover of the CMRO application, with high impact to confidentiality, integrity, and availability. No patch, public proof-of-concept, or known exploitation in the wild has been confirmed at the time of writing.

Technical Analysis

The vulnerability resides in the Internal Operations component of Oracle Complex Maintenance, Repair and Overhaul within Oracle E-Business Suite. The NVD description characterizes it as an "easily exploitable" issue that a low-privileged attacker can reach over the network via HTTPS. Successful exploitation results in "takeover of Oracle Complex Maintenance, Repair and Overhaul," meaning the attacker gains control over the application's function and data rather than merely reading a single record.

The CVSS 3.1 vector (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) tells us the following about the attack surface and mechanics:

• AV:N (Network) — the flaw is reachable remotely, not restricted to local or adjacent access. The description specifically states HTTPS, so the entry point is a web-facing Oracle E-Business Suite endpoint exposing CMRO functionality.
• AC:L (Low complexity) — no race condition, no specialized memory-layout grooming, or unusual preconditions are required. The attack is repeatable with minimal effort.
• PR:L (Low privileges) — the attacker must possess a valid, low-privileged account. This is significant: the flaw does not require administrative credentials, so a compromised standard user or self-registered low-privilege account is sufficient. Unauthenticated attacks are not indicated by the vector.
• UI:N (No user interaction) — no victim needs to click a link or open a file.
• S:U (Unchanged scope) — the exploited component remains the same security authority; the impact does not formally cross into other components per the CVSS scope definition.
• C:H/I:H/A:H — full compromise of confidentiality, integrity, and availability of the vulnerable component.

The described outcome — "takeover" — combined with the low-privilege precondition strongly indicates a broken access control / privilege escalation class weakness: a low-privileged user is able to invoke functionality or access objects that should be restricted to higher-privileged roles, ultimately gaining control over the CMRO application. Because the CNA title and NVD description do not disclose the specific endpoint, parameter, or code path, the underlying CWE cannot be confirmed; no CWE is assigned in the provided data. Analysis should therefore focus on the vulnerability class (access control bypass within the Internal Operations component reachable over HTTPS) rather than an assumed implementation detail.

Note on uncertainty: the specific vulnerable endpoint, the exact privilege boundary bypassed, and the precise code-level mechanism are not disclosed in the provided intelligence. Any statement identifying a specific API path, parameter name, or function would be fabrication and is deliberately omitted. This report describes the attack at the vulnerability-class level, consistent with the available data.

A further consideration is that Oracle E-Business Suite deployments are frequently internet-exposed to support external suppliers, contractors, and maintenance partners — precisely the kind of users that hold low-privileged accounts. The CMRO module is used for complex asset maintenance scheduling and work-order management, meaning its data set is operationally sensitive. Taken together, the vulnerability is attractive to an attacker already holding any foothold in the EBS environment.

Exploitation Scenarios

No public proof-of-concept, exploit code, or Nuclei template exists for CVE-2026-83445 at the time of writing (POC_STATUS: None). The attack chain below is inferred from the vulnerability class and the CVSS vector; it deliberately avoids fabricating specific endpoints, parameters, or function names not present in the source data.

1. Reconnaissance / target identification

   • The attacker identifies an internet- or partner-facing Oracle E-Business Suite deployment running versions 12.2.3 through 12.2.15 with the Complex Maintenance, Repair and Overhaul module enabled. Shodan and similar scanning services can fingerprint EBS login portals and CMRO-related pages.
   • Because the flaw requires low privileges (PR:L), the attacker establishes or obtains any valid low-privileged account — for example, a self-registered, contractor, or compromised standard user account.

2. Triggering the flaw

   • The attacker authenticates over HTTPS as the low-privileged user and navigates to the CMRO Internal Operations functionality. The flaw is an access-control weakness that permits the low-privileged user to perform actions or reach data beyond their assigned role. No user interaction is required (UI:N) and complexity is low (AC:L), so the attack is direct and repeatable.

3. Execution / payload at the vulnerability-class level

   • The "payload" here is an unauthorized privileged request rather than memory-corruption shellcode. The attacker issues a crafted request over HTTPS to the CMRO Internal Operations surface that the application fails to authorize correctly for a low-privileged principal. No public PoC is available; the precise request format is inferred from the vulnerability class.

4. Post-exploitation impact

   • Successful exploitation results in takeover of Oracle Complex Maintenance, Repair and Overhaul, which the CVSS scores reflect as high confidentiality, integrity, and availability impact. The attacker can read, modify, or disrupt CMRO operations and data, and can leverage the application context for further lateral movement within the E-Business Suite environment. Because scope is Unchanged (S:U), the primary impact is contained to the CMRO/Internal Operations component authority.

Impact Assessment

CVE-2026-83445 carries a CVSS 3.1 Base Score of 8.8, placing it in the High severity band. The subscores are:

• Confidentiality: High — sensitive maintenance, repair, and overhaul records, including operational and potentially contractual data, are exposed.
• Integrity: High — an attacker can alter CMRO data and process state, undermining the reliability of maintenance and asset records.
• Availability: High — the application can be disrupted as part of the takeover.

The attack is network-reachable and low-complexity with only low privileges required, so the primary barrier to exploitation is obtaining any valid account, not specialist skill. Business impact centers on operations that depend on CMRO: maintenance scheduling, work orders, asset history, and supplier/partner workflows. Compromise of these records can cause safety-relevant asset-maintenance errors, contractual and compliance exposure, and loss of trust in operational data. The blast radius is the vulnerable CMRO component and its integrated data; because scope is Unchanged in the CVSS model, the vector does not assert cross-component impact, but operators should assume further movement may be possible given the "takeover" severity. No exploited-in-the-wild evidence currently exists, which lowers immediate urgency while the exposure window is addressed.

Detection Guidance

Sigma Rule

title: Oracle E-Business Suite CMRO Low-Privilege Access Control Bypass Attempt
id: 7d5c2f19-3b6a-4e21-9f8a-2c0e1b7a5d44
status: experimental
description: Detects anomalous low-privileged access to Oracle E-Business Suite Complex Maintenance, Repair and Overhaul (CMRO) Internal Operations, potentially exploiting CVE-2026-83445 access control bypass.
references:
  - https://nvd.nist.gov/vuln/detail/CVE-2026-83445
author: SOC Threat Intelligence
date: 2026-01-01
logsource:
  category: webserver
  product: oracle
detection:
  selection_path:
    cs-uri-stem|contains:
      - '/OA_HTML/'
      - '/oracle/apps/'
      - 'CMRO'
  selection_cmro:
    cs-uri-stem|contains:
      - 'Maintenance'
      - 'Repair'
      - 'Overhaul'
      - 'InternalOperations'
  selection_priv:
    cs-username|exists: true
  filter_admin:
    cs-username|contains:
      - 'ADMIN'
      - 'SYSADMIN'
  condition: selection_path and selection_cmro and selection_priv and not filter_admin
falsepositives:
  - Legitimate CMRO access by authorized maintenance roles
level: high
tags:
  - attack.t1190
  - cve.2026.83445

YARA Rule

rule CVE_2026_83445_CMRO_AccessBypass
{
    meta:
        description = "Detects suspicious request patterns targeting Oracle E-Business Suite CMRO Internal Operations possibly exploiting CVE-2026-83445"
        author = "SOC Threat Intelligence"
        date = "2026-01-01"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2026-83445"
        severity = "high"

    strings:
        $cmro1 = "Complex Maintenance, Repair and Overhaul" ascii nocase wide
        $cmro2 = "Internal Operations" ascii nocase wide
        $ebs1  = "E-Business Suite" ascii nocase wide
        $path1 = "/OA_HTML/" ascii nocase wide
        $http1 = "POST /" ascii
        $http2 = "GET /" ascii

    condition:
        (uint16(0) == 0x4D5A or uint16(0) == 0x504B or filesize > 0) and
        (any of ($cmro*) or $ebs1) and
        ($path1 or $http1 or $http2)
}

Suricata IDS Rule

alert http any any -> any any (msg:"CVE-2026-83445 Oracle E-Business Suite CMRO Internal Operations Suspicious Access"; flow:established,to_server; http.method; content:"POST"; http.uri; content:"/OA_HTML/"; http.uri; content:"CMRO"; nocase; http.header; content:"Cookie"; threshold:type both, track by_src, count 5, seconds 60; classtype:attempted-admin; reference:url,nvd.nist.gov/vuln/detail/CVE-2026-83445; sid:202683445; rev:1;)

Elastic Detection

sequence by source.ip with maxspan=2m
  [network where http.request.method == "POST" and url.path : "/OA_HTML/*" and url.path : "*CMRO*"]
  [http where http.response.status_code == 200 and url.path : "*InternalOperations*"]

Splunk SPL Query

index=web sourcetype=oracle:ebs OR sourcetype=access_combined
| search (uri_path="/OA_HTML/*" OR uri_path="*CMRO*" OR uri_path="*InternalOperations*")
| search cs_username!=*ADMIN* cs_username!=*SYSADMIN*
| stats count min(_time) as first_seen max(_time) as last_seen values(uri_path) as paths by src_ip cs_username
| where count > 5
| eval first_seen=strftime(first_seen,"%Y-%m-%d %H:%M:%S"), last_seen=strftime(last_seen,"%Y-%m-%d %H:%M:%S")
| sort - count

Wazuh OSSEC Rule

<group name="oracle,ebs,web,">
  <rule id="2026834" level="12">
    <decoded_as>web-accesslog</decoded_as>
    <url>/OA_HTML/</url>
    <url>CMRO</url>
    <description>CVE-2026-83445 possible exploitation attempt: low-privileged access to Oracle E-Business Suite CMRO Internal Operations</description>
    <mitre>
      <id>T1190</id>
    </mitre>
    <group>cve_2026_83445,access_control,</group>
  </rule>
</group>

Mitigation & Patch Guidance

Patch confidence: 0/4 (UNPATCHED — no patch evidence from any tracked source). No vendor fix, fix version, or workaround has been identified in the provided intelligence. Do not assume a fixed release exists; verify against Oracle's Critical Patch Update (CPU) advisories.

1. Immediate mitigations

   • Restrict network reachability of Oracle E-Business Suite, particularly the CMRO and Internal Operations surfaces, to trusted networks, VPN, or a WAF/reverse proxy that performs authentication and request inspection. Remove unnecessary internet exposure of EBS.
   • Enforce least privilege: audit CMRO user roles and eliminate unnecessary low-privileged accounts, especially contractor and self-registered accounts.
   • Enable and centralize EBS web and application logs, and deploy the detection rules in this report to monitor for anomalous low-privileged access to CMRO Internal Operations.

2. Patch / upgrade steps

   • Monitor Oracle Critical Patch Update (CPU) advisories for the CVE-2026-83445 fix covering E-Business Suite 12.2.3–12.2.15. Apply the vendor patch as soon as it is published.
   • Until a patch is available, apply Oracle's standard EBS security hardening guidance (patch current CPU levels, restrict access, review role assignments).

3. Long-term hardening

   • Integrate Oracle CPUs into a tracked patch-management cycle with defined SLAs for high-severity issues.
   • Implement robust authorization testing in change management for CMRO and other EBS modules.
   • Deploy continuous access-control monitoring and periodic privilege recertification for EBS roles.
   • Maintain network segmentation between EBS and general corporate/partner networks to limit lateral movement if CMRO is compromised.

References

• NVD — CVE-2026-83445: https://nvd.nist.gov/vuln/detail/CVE-2026-83445
• Oracle Critical Patch Updates and Security Alerts: https://www.oracle.com/security-alerts/
• Oracle E-Business Suite (Complex Maintenance, Repair and Overhaul) product documentation: https://www.oracle.com/applications/ebusiness/
• MITRE ATT&CK T1190 — Exploit Public-Facing Application: https://attack.mitre.org/techniques/T1190/
• FIRST EPSS: no score currently available for CVE-2026-83445 (not yet scored by FIRST.org)

Threat actor campaign note: No known threat actor campaigns or exploit-in-the-wild evidence are documented for CVE-2026-83445 at the time of writing. CISA KEV status: NO. No public PoC, exploit code, or Nuclei template is available.