Medium
Boards plugin retains Board Admin rights for users demoted to System Guest
Type: advisorySources: OSV
Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21, 11.8.x <= 11.8.3 fails to reconcile SchemeAdmin flags with a user's current role which allows a user demoted to System Guest to retain Board Admin privileges and perform admin-only operations via the Boards REST API or UI.. Mattermost Advisory ID: MMSA-2026-00691
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-10527
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 2 Nov 2026, 18:49 UTC · Revision 1
Source evidence
Boards plugin retains Board Admin rights for users demoted to System Guest
core-osv · Original sourcePublished 17 Aug 2026, 14:37 UTC
Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21, 11.8.x <= 11.8.3 fails to reconcile SchemeAdmin flags with a user's current role which allows a user demoted to System Guest to retain Board Admin privileges and perform admin-only operations via the Boards REST API or UI.. Mattermost Advisory ID: MMSA-2026-00691
osv:CVE-2026-10527
Complete source record
{
"id": "a12fb2902441fd50757f18219b091658c31ada67a7460e71366053f741117d6e",
"url": "https://osv.dev/vulnerability/CVE-2026-10527",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "Boards plugin retains Board Admin rights for users demoted to System Guest",
"summary": "Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21, 11.8.x <= 11.8.3 fails to reconcile SchemeAdmin flags with a user's current role which allows a user demoted to System Guest to retain Board Admin privileges and perform admin-only operations via the Boards REST API or UI.. Mattermost Advisory ID: MMSA-2026-00691",
"evidence": "osv:CVE-2026-10527",
"products": [],
"severity": "medium",
"structured": {
"id": "CVE-2026-10527",
"aliases": [
"CVE-2026-10527"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/mattermost/mattermost",
"type": "GIT",
"events": [
{
"introduced": "5b955468ea1ea8b56c0fb10feb258a36a767d7bb"
},
{
"fixed": "d6dbfe06f8abbe0d9d57cf47dc322042a826eb42"
},
{
"introduced": "a9e574a82633915f22071f0d7ca2b006f249ec2a"
},
{
"fixed": "2045acd92c40353abfc5ffff8ae1e0dd9d2e6737"
},
{
"introduced": "e8bd2b8a871cbeff6943bead62328478118188df"
},
{
"fixed": "92d79e4d0cda808c3f63217a62d068472c184099"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "10.11.0"
},
{
"fixed": "10.11.22"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "11.7.0"
},
{
"fixed": "11.7.7"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "11.8.0"
},
{
"fixed": "11.8.4"
}
],
"source": "CPE_RANGE"
}
]
}
}
],
"versions": [
"v11.8.3",
"v10.11.21",
"v11.7.6",
"v11.8.2",
"v11.7.5-rc1",
"v11.7.5",
"v11.8.1",
"v11.7.4",
"v11.7.3",
"v10.11.20",
"v11.8.0-rc5",
"v11.8.0",
"mattermost-redux@11.8.0",
"@mattermost/types@11.8.0",
"@mattermost/shared@11.8.0",
"@mattermost/client@11.8.0",
"v10.11.19",
"v10.11.19-rc1",
"v11.7.2",
"v10.11.18",
"v11.7.1",
"v10.11.17",
"v10.11.16",
"v11.7.0",
"mattermost-redux@11.7.0",
"@mattermost/types@11.7.0",
"@mattermost/shared@11.7.0",
"@mattermost/client@11.7.0",
"v10.11.15-rc1",
"v10.11.15",
"v10.11.14",
"v10.11.14-rc1",
"v10.11.13",
"v10.11.13-rc1",
"v10.11.12",
"v10.11.11-rc2",
"v10.11.11",
"v10.11.11-rc1",
"v10.11.10",
"v10.11.9",
"v10.11.9-rc1",
"v10.11.8",
"v10.11.7",
"v10.11.6",
"v10.11.5",
"v10.11.4-rc3",
"v10.11.4",
"v10.11.4-rc2",
"v10.11.4-rc1",
"v10.11.3",
"v10.11.2-rc2",
"v10.11.2",
"v10.11.2-rc1",
"v10.11.1",
"v10.11.1-rc1",
"v10.11.0-rc3",
"v10.11.0",
"mattermost-redux@10.11.0",
"@mattermost/types@10.11.0",
"@mattermost/client@10.11.0"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-10527.json"
}
}
],
"modified": "2026-10-28T02:30:22.342950532Z",
"provider": "osv",
"references": [
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/10xxx/CVE-2026-10527.json",
"https://mattermost.com/security-updates",
"https://nvd.nist.gov/vuln/detail/CVE-2026-10527"
],
"provider_metadata": {
"cwe_ids": [
"CWE-863"
],
"cna_assigner": "Mattermost",
"unresolved_ranges": [
{
"extracted_events": [
{
"range": [
{
"introduced": "11.7.0"
},
{
"last_affected": "11.7.6"
},
{
"introduced": "10.11.0"
},
{
"last_affected": "10.11.21"
},
{
"introduced": "11.8.0"
},
{
"last_affected": "11.8.3"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StandardRange"
}
]
}
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/10xxx/CVE-2026-10527.json"
}
},
"related_cves": [
{
"value": "CVE-2026-10527",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 488778,
"published_at": "2026-08-17T14:37:46.253+00:00"
}