Mattermost versions 10.11.x <= 10.11.20, 11.7.x <= 11.7.5 Mattermost fails to remove thread membership records when a user is removed from or leaves a team, which allows a previously removed user who is later re-invited to the team to view private channel thread root post content and metadata via the team threads API.. Mattermost Advisory ID: MMSA-2026-00682
{
"unresolved_ranges": [
{
"source": "AFFECTED_FIELD",
"extracted_events": [
{
"introduced": "10.11.0"
},
{
"last_affected": "10.11.20"
},
{
"introduced": "11.7.0"
},
{
"last_affected": "11.7.5"
}
]
}
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/9xxx/CVE-2026-9693.json",
"cna_assigner": "Mattermost",
"cwe_ids": [
"CWE-459"
]
}{
"source": "CPE_RANGE",
"cpe": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*",
"extracted_events": [
{
"introduced": "10.11.0"
},
{
"fixed": "10.11.21"
},
{
"introduced": "11.7.0"
},
{
"fixed": "11.7.6"
}
]
}