Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 fail to restrict role_updated websocket event broadcasts to members of the affected team or channel which allows an authenticated attacker with guest-level access to observe permission scheme change notifications for private teams they are not a member of via the websocket connection.. Mattermost Advisory ID: MMSA-2026-00616
{
"cwe_ids": [
"CWE-200"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/3xxx/CVE-2026-3433.json",
"unresolved_ranges": [
{
"extracted_events": [
{
"introduced": "11.6.0"
},
{
"last_affected": "11.6.1"
},
{
"introduced": "11.5.0"
},
{
"last_affected": "11.5.4"
},
{
"introduced": "10.11.0"
},
{
"last_affected": "10.11.15"
},
{
"introduced": "10.11.0"
},
{
"last_affected": "10.11.16"
}
],
"source": "AFFECTED_FIELD"
}
],
"cna_assigner": "Mattermost"
}{
"cpe": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*",
"extracted_events": [
{
"introduced": "10.11.0"
},
{
"fixed": "10.11.17"
},
{
"introduced": "11.5.0"
},
{
"fixed": "11.5.5"
},
{
"introduced": "11.6.0"
},
{
"fixed": "11.6.2"
}
],
"source": "CPE_RANGE"
}