How severe is CVE-2026-53909?

CVE-2026-53909 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2026-53909 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-53909?

CVE-2026-53909 affects Mycomplianceoffice. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-53909?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2026-53909 published?

CVE-2026-53909 was published on 2026-07-01 and last updated on 2026-07-06.

CVE-2026-53909

CVE-2026-53909 is a medium-severity vulnerability in Mycomplianceoffice with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-434.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v4: 5.3
EPSS exploit prediction: 0% (13th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-434
Affected product: Mycomplianceoffice
Published: 2026-07-01
Last modified: 2026-07-06

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.

Frequently asked questions

What is CVE-2026-53909?: 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.
How severe is CVE-2026-53909?: CVE-2026-53909 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2026-53909 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-53909?: CVE-2026-53909 affects Mycomplianceoffice. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-53909?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2026-53909 published?: CVE-2026-53909 was published on 2026-07-01 and last updated on 2026-07-06.

References

Affected products (1)

cpe:2.3:a:mycomplianceoffice:mycomplianceoffice:25.3.3.1:*:*:*:*:*:*:*

More vulnerabilities in Mycomplianceoffice

CVE-2026-53906 — High (CVSS 8.2): MCO is vulnerable to Path Disclosure and Path Traversal in file handling functionality related to data export and…
CVE-2026-53903 — High (CVSS 8.1): MCO is vulnerable to an Insecure Direct Object Reference (IDOR) vulnerability in the…
CVE-2026-53905 — High (CVSS 7.1): MCO does not properly enforce authorization checks in the /customer/servlet/mco/webapi/admin-view-hierarchy/get-acl-tree…
CVE-2026-53902 — Medium (CVSS 6.5): MCO does not properly enforce authorization checks in the /customer/servlet/mco/webapi/profile-sections/group-membership…
CVE-2026-53907 — Medium (CVSS 5.4): MCO is vulnerable to Stored Cross‑Site Scripting (XSS) via the application logo upload functionality. An attacker…
CVE-2026-53908 — Medium (CVSS 4.3): MCO is vulnerable to User Enumeration through authentication-related functionalities. The application returns…

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