{
"id": "GHSA-8qq9-cqj8-82w4",
"aliases": [
"CVE-2026-6961"
],
"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 sanitize FileInfo.Name received from federated peers during shared channel file sync, which allows an attacker who controls a federated server to write files to arbitrary locations within the target server's filestore via path traversal sequences in the filename field. Mattermost Advisory ID: MMSA-2026-00661",
"summary": "Mattermost doesn't sanitize FileInfo.Name received from federated peers during shared channel file sync",
"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": "8.0.0-20260423180926-c021eeaff8f0"
}
]
}
],
"package": {
"name": "github.com/mattermost/mattermost/server/v8",
"ecosystem": "Go"
}
}
],
"modified": "2026-08-24T21:45:52Z",
"severity": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:H/A:L"
}
],
"published": "2026-06-12T18:31:59Z",
"references": [
{
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-6961",
"type": "ADVISORY"
},
{
"url": "https://github.com/mattermost/mattermost/pull/36255",
"type": "WEB"
},
{
"url": "https://github.com/mattermost/mattermost/pull/36253",
"type": "WEB"
},
{
"url": "https://github.com/mattermost/mattermost/pull/36252",
"type": "WEB"
},
{
"url": "https://github.com/mattermost/mattermost/pull/36251",
"type": "WEB"
},
{
"url": "https://github.com/mattermost/mattermost/pull/36223",
"type": "WEB"
},
{
"url": "https://github.com/mattermost/mattermost/commit/c896a63dc44c2f9c081a0a15bfddc4e6eb50e753",
"type": "WEB"
},
{
"url": "https://github.com/mattermost/mattermost/commit/c021eeaff8f003034ab40f82c552cc26a710a8fd",
"type": "WEB"
},
{
"url": "https://github.com/mattermost/mattermost/commit/a9f3868e1eee9ec61855cd7277f39937385efffd",
"type": "WEB"
},
{
"url": "https://github.com/mattermost/mattermost/commit/a0056ed68d95f64d7c4586985e7b7f16b96b3bec",
"type": "WEB"
},
{
"url": "https://github.com/mattermost/mattermost/commit/61d68d2d6ee81a5919597d91c736c502d7156859",
"type": "WEB"
},
{
"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"
},
{
"url": "https://github.com/mattermost/mattermost",
"type": "PACKAGE"
}
],
"schema_version": "1.4.0",
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"severity": "HIGH",
"github_reviewed": true,
"nvd_published_at": "2026-06-12T17:16:27Z",
"github_reviewed_at": "2026-08-24T21:45:51Z"
}
}