# CVE-2026-53907: MyComplianceOffice MCO Stored XSS in logo upload

Source: https://junglewise.ai/threats/cve-2026-53907-mycomplianceoffice-mco-stored-xss-in-logo-upload  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-01. Updated: 2026-07-01  
License: CC BY 4.0 with a link back

CVE-2026-53907 · Severity: info · CVSS 4.8 · Published 2026-07-01

MyComplianceOffice (MCO) is a compliance management platform used by financial services and insurance firms to automate regulatory oversight. A security flaw in the application's logo upload feature allows an attacker with administrative privileges to upload a malicious image file. If this file is viewed by other users, it could allow the attacker to hijack their sessions or perform unauthorized actions within the platform.

Technologies: [MyComplianceOffice MCO](https://junglewise.ai/threats/technologies/mco). Vendors: [MyComplianceOffice](https://junglewise.ai/threats/vendors/mycomplianceoffice).

## Quick answers

**Is CVE-2026-53907 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-53907 being exploited in the wild.

**How severe is CVE-2026-53907?** Informational severity, with a CVSS score of 4.8, published 1 July 2026.

**Which products and versions are affected?** MyComplianceOffice MCO 25.3.3.1.

**Is there a fix for CVE-2026-53907?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-53907 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-53907?** Check whether you run MyComplianceOffice MCO at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A Stored Cross-Site Scripting (XSS) vulnerability exists in MyComplianceOffice (MCO) version 25.3.3.1. The flaw is located in the application logo upload functionality, which fails to properly sanitize uploaded SVG files. An authenticated attacker with permissions to modify the application logo can upload a crafted SVG containing malicious JavaScript. This script executes in the context of any user who renders or opens the logo file. While exploitation requires high privileges (PR:H) and some user interaction (UI:P), it can lead to session hijacking or unauthorized data access within the web interface. No patch is currently confirmed as vendor contact attempts were unsuccessful.

## Affected products

- MyComplianceOffice MCO 25.3.3.1

## Timeline

- 2026-07-01: advisory: Advisory published by CERT Polska
- 2026-07-01: disclosed: CVE-2026-53907 published to NVD

## References

- [https://cert.pl/en/posts/2026/07/CVE-2026-53902](https://cert.pl/en/posts/2026/07/CVE-2026-53902)
- [https://mco.mycomplianceoffice.com/](https://mco.mycomplianceoffice.com/)

## Related threats

- [MyComplianceOffice MCO Unrestricted File Upload](https://junglewise.ai/threats/cve-2026-53909-mycomplianceoffice-mco-unrestricted-file-upload)
- [MyComplianceOffice MCO user enumeration in authentication components](https://junglewise.ai/threats/cve-2026-53908-mycomplianceoffice-mco-user-enumeration-in-authentication)
- [MyComplianceOffice MCO path traversal and path disclosure in file handling](https://junglewise.ai/threats/cve-2026-53906-mycomplianceoffice-mco-path-traversal-and-path-disclosure-in-file)
- [MyComplianceOffice MCO Incorrect Authorization in ACL Tree Endpoint](https://junglewise.ai/threats/cve-2026-53905-mycomplianceoffice-mco-incorrect-authorization-in-acl-tree)
- [MyComplianceOffice MCO Account Denial of Service in password reset](https://junglewise.ai/threats/cve-2026-53904-mycomplianceoffice-mco-account-denial-of-service-in-password)