Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7 fail to enforce authorization boundaries on the access control policy update endpoint which allows a channel or team administrator to detach a system-assigned ABAC parent policy via a crafted PUT /api/v4/access_control_policies request with an empty imports list.. Mattermost Advisory ID: MMSA-2026-00724
{
"cna_assigner": "Mattermost",
"cwe_ids": [
"CWE-863"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/82xxx/CVE-2026-82920.json",
"unresolved_ranges": [
{
"extracted_events": [
{
"introduced": "11.8.0"
},
{
"last_affected": "11.8.4"
},
{
"introduced": "11.7.0"
},
{
"last_affected": "11.7.7"
},
{
"introduced": "11.9.0"
},
{
"last_affected": "11.9.0"
}
],
"source": "AFFECTED_FIELD"
}
]
}{
"cpe": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*",
"extracted_events": [
{
"introduced": "11.7.0"
},
{
"fixed": "11.7.8"
},
{
"introduced": "11.8.0"
},
{
"fixed": "11.8.5"
},
{
"introduced": "11.9.0"
},
{
"fixed": "11.9.1"
}
],
"source": "CPE_RANGE"
}