Is CVE-2026-28736 actively exploited?

CVE-2026-28736 has no public evidence of in-the-wild exploitation as of 2026-04-28.

What is the CVSS score for CVE-2026-28736?

CVE-2026-28736 has a CVSS score of 4.3 (MEDIUM severity). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.

How do I patch CVE-2026-28736?

Patch guidance is available from mattermost security advisories. CVEDatabase generates AI-assisted remediation guidance on demand for CVE-2026-28736.

Which products are affected by CVE-2026-28736?

1 product: mattermost focalboard.

CVE-2026-28736 - remediation guidance & executive summary

Description

** UNSUPPORTED WHEN ASSIGNED ** Focalboard version 8.0 fails to validate file ownership when serving uploaded files. This allows an authenticated attacker who knows a victim's fileID to read the content of the file. NOTE: Focalboard as a standalone product is not maintained and no fix will be issued.

CVSS Metrics

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Attack Vector: network
Complexity: low
Privileges: low
User Action: none
Scope: unchanged
Confidentiality: low
Integrity: none
Availability: none
Weaknesses: CWE-639

Metadata

Primary Vendor: MATTERMOST
Published: 4/3/2026
Last Modified: 4/28/2026
Source: NIST NVD
Note: Verify all details with official vendor sources before applying patches.

Affected Products

mattermost : focalboard

Remediation Guidance

Executive Summary

Cite this page

CVE-2026-28736. CVEDatabase.com. Retrieved 1 May 2026. https://cvedatabase.com/cve/CVE-2026-28736

View on NIST NVD

CVE-2026-28736 vulnerability