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01 Record

CVE-2026-28736

Focalboard IDOR in file content endpoint allows cross-user file access (unsupported product, no fix)

MediumPUBLISHEDCNA: Mattermost
CNA base score4.3 CVSS v3.xCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

02 Description

Focalboard IDOR in file content endpoint allows cross-user file access (unsupported product, no fix)

03 Exploitation and scoring

Exploitation
Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.
SSVC decision
  • ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
  • AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
  • Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.
CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.
EPSS probability
0.22% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 12.5% of scored records. A rank, not a probability.
NVD base score
4.3 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
NVD analysis status
Analyzed. NVD last modified this record on 2026-10-23.
Red Hat severity
No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published
2026-04-03 13:25Z6 MO AGO
Last updated
2026-04-03 14:54Z6 MO AGO
Reserved
2026-04-03
Assigning CNA
Mattermost
Record state
PUBLISHED
Severity
Medium (CVSS 4.3)
CNA CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Weaknesses
  • CWE-639Authorization Bypass Through User-Controlled KeyBase
Data version
5.2
Document digest
0a3d1b06b5bd9d59a818c5368135c307701ac73cd4ad7070b6ad00dd68550137

05 Affected products

VendorProductVersionsPlatforms
MattermostFocalboard0 to 8.0—

06 References