CVE-2026-53903
CWE-639Published: July 1, 2026· Updated: Jul 1, 2026
Official Description
MCO is vulnerable to an Insecure Direct Object Reference (IDOR) vulnerability in the /customer/servlet/mco/webapi/trading-document/fetchPdfStatement endpoint. The application does not properly validate whether an authenticated user is authorized to access a requested document, allowing direct retrieval based on a user-supplied identifier.
An attacker can access trading documents belonging to other users by providing a valid document ID. Although exploitation requires guessing the identifier, predictable ID patterns enable feasible enumeration, leading to unauthorized disclosure of sensitive information.
Because vendor contact attempts were unsuccessful, the vulnerability has only been confirmed in version 25.3.3.1 but may also affect other versions.
Technical Analysis
CVE-2026-53903 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
CVSS v3.1 Vector Breakdown
Exploit & PoC Resources
All References (2)
Quick Facts
Related CVEs (CWE-639)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2026-53903 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts