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Vulnerability record · CVE-2026-53909 · published 1 July 2026

CVE-2026-53909: Mycomplianceoffice unrestricted file upload vulnerability

Mycomplianceoffice · Mycomplianceoffice

MCO does not correctly validate types of uploaded files. File upload validation functionality relies only on client-side checks, which can be bypassed. An authorized, low-privileged attacker can upload files with arbitrary types to the server. Because vendor contact attempts were unsuccessful, the vulnerability has only been confirmed in version 25.3.3.1 but may also affect other versions.

5.3 CVSS 4.0 Medium EPSS 0.39% · top 69.0% CWE-434 · Unrestricted file upload
5.3CVSS 4.0 base score
0.39%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References
6 Jul 2026Last modified by NVD

Description

MCO does not correctly validate types of uploaded files. File upload validation functionality relies only on client-side checks, which can be bypassed. An authorized, low-privileged attacker can upload files with arbitrary types to the server. Because vendor contact attempts were unsuccessful, the vulnerability has only been confirmed in version 25.3.3.1 but may also affect other versions.

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://cert.pl/en/posts/2026/07/CVE-2026-53902 Third Party Advisory
https://mco.mycomplianceoffice.com/ Product

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

7.1CVE-2026-53902Mycomplianceoffice incorrect authorization vulnerabilityMCO does not properly enforce authorization checks in the /customer/servlet/mco/webapi/profile-sections/group-membership endpoint. An authenticated u…EPSS 0.34%6.9CVE-2026-53908Mycomplianceoffice vulnerabilityMCO is vulnerable to User Enumeration through authentication-related functionalities. The application returns distinguishable responses for valid and…EPSS 0.36%5.3CVE-2026-53903Mycomplianceoffice insecure direct object reference vulnerabilityMCO is vulnerable to an Insecure Direct Object Reference (IDOR) vulnerability in the /customer/servlet/mco/webapi/trading-document/fetchPdfStatement …EPSS 0.41%5.3CVE-2026-53905Mycomplianceoffice incorrect authorization vulnerabilityMCO does not properly enforce authorization checks in the /customer/servlet/mco/webapi/admin-view-hierarchy/get-acl-tree-structure endpoint. An authe…EPSS 0.32%5.1CVE-2026-53906Mycomplianceoffice path traversal vulnerabilityMCO is vulnerable to Path Disclosure and Path Traversal in file handling functionality related to data export and upload. Improper validation of the …EPSS 0.52%4.8CVE-2026-53907Mycomplianceoffice cross-site scripting vulnerabilityMCO is vulnerable to Stored Cross‑Site Scripting (XSS) via the application logo upload functionality. An attacker with the ability to change the appl…EPSS 0.24%10.0CVE-2026-56291Balbooa Forms Joomla extension unauthenticated arbitrary file upload RCEThe Balbooa Forms extension for Joomla before version 2.4.1 accepts file uploads without authentication and does not restrict file type, allowing exe…KEVEPSS 15%analysed10.0CVE-2026-48939iCagenda Joomla extension unrestricted file upload leads to PHP RCEThe iCagenda extension for Joomla fails to restrict file types in its file attachment feature, allowing arbitrary file uploads that result in PHP cod…KEVEPSS 20%analysed

Source: NIST National Vulnerability Database (record CVE-2026-53909), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.