{
"id": "GHSA-rp4v-qc77-phm4",
"aliases": [
"CVE-2026-3433"
],
"details": "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",
"summary": "Mattermost doesn't restrict role_updated websocket event broadcasts to members of the affected team or channel",
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "11.6.0"
},
{
"fixed": "11.6.1"
}
]
}
],
"package": {
"name": "github.com/mattermost/mattermost-server",
"ecosystem": "Go"
},
"versions": [
"11.6.0"
]
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "11.5.0"
},
{
"fixed": "11.5.5"
}
]
}
],
"package": {
"name": "github.com/mattermost/mattermost-server",
"ecosystem": "Go"
},
"database_specific": {
"last_known_affected_version_range": "<= 11.5.4"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "10.11.0"
},
{
"fixed": "10.11.17"
}
]
}
],
"package": {
"name": "github.com/mattermost/mattermost-server",
"ecosystem": "Go"
},
"database_specific": {
"last_known_affected_version_range": "<= 10.11.15"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "8.0.0-20250731163400-5b955468ea1e"
},
{
"fixed": "8.0.0-20260504071740-9408b98025d7"
}
]
}
],
"package": {
"name": "github.com/mattermost/mattermost/server/v8",
"ecosystem": "Go"
}
}
],
"modified": "2026-08-24T21:30:50Z",
"severity": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N"
}
],
"published": "2026-06-12T18:31:59Z",
"references": [
{
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-3433",
"type": "ADVISORY"
},
{
"url": "https://github.com/mattermost/mattermost/pull/35497",
"type": "WEB"
},
{
"url": "https://github.com/mattermost/mattermost/pull/36256",
"type": "WEB"
},
{
"url": "https://github.com/mattermost/mattermost/pull/36257",
"type": "WEB"
},
{
"url": "https://github.com/mattermost/mattermost/pull/36341",
"type": "WEB"
},
{
"url": "https://github.com/mattermost/mattermost/commit/0a0ab0d54d899d308bd1352cc577036917500318",
"type": "WEB"
},
{
"url": "https://github.com/mattermost/mattermost/commit/7425c6817bf244f976c729f8a73cecac8039a1e1",
"type": "WEB"
},
{
"url": "https://github.com/mattermost/mattermost/commit/9408b98025d7364d7dfe7cdb28fcd109b1b595a6",
"type": "WEB"
},
{
"url": "https://github.com/mattermost/mattermost/commit/a30a331a29b9766d46716d4252056d7b74e66da0",
"type": "WEB"
},
{
"url": "https://github.com/mattermost/mattermost",
"type": "PACKAGE"
},
{
"url": "https://github.com/mattermost/mattermost/releases/tag/v10.11.16",
"type": "WEB"
},
{
"url": "https://github.com/mattermost/mattermost/releases/tag/v11.5.5",
"type": "WEB"
},
{
"url": "https://github.com/mattermost/mattermost/releases/tag/v11.6.2",
"type": "WEB"
},
{
"url": "https://github.com/mattermost/mattermost/releases/tag/v11.7.0",
"type": "WEB"
},
{
"url": "https://mattermost.com/security-updates",
"type": "WEB"
}
],
"schema_version": "1.4.0",
"database_specific": {
"cwe_ids": [
"CWE-200"
],
"severity": "MODERATE",
"github_reviewed": true,
"nvd_published_at": "2026-06-12T17:16:22Z",
"github_reviewed_at": "2026-08-24T21:30:50Z"
}
}