Medium
Slash command trigger-word update allowed command hijacking
Type: advisorySources: OSV
Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 Fail to enforce slash command trigger-word uniqueness during command updates which allows an authenticated team member with Manage Own Slash Commands permission to hijack and impersonate existing system or custom slash commands via editing their own slash command trigger to an already-registered trigger through the command update API. Mattermost Advisory ID: MMSA-2026-00597
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-28732
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 8 Nov 2026, 02:29 UTC · Revision 1
Source evidence
Slash command trigger-word update allowed command hijacking
core-osv · Original sourcePublished 18 May 2026, 08:35 UTC
Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 Fail to enforce slash command trigger-word uniqueness during command updates which allows an authenticated team member with Manage Own Slash Commands permission to hijack and impersonate existing system or custom slash commands via editing their own slash command trigger to an already-registered trigger through the command update API. Mattermost Advisory ID: MMSA-2026-00597
osv:CVE-2026-28732
Complete source record
{
"id": "6a989058d6cee406026bb4fe792ef5888507b191be99de057bc1963d050931fe",
"url": "https://osv.dev/vulnerability/CVE-2026-28732",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "Slash command trigger-word update allowed command hijacking",
"summary": "Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 Fail to enforce slash command trigger-word uniqueness during command updates which allows an authenticated team member with Manage Own Slash Commands permission to hijack and impersonate existing system or custom slash commands via editing their own slash command trigger to an already-registered trigger through the command update API. Mattermost Advisory ID: MMSA-2026-00597",
"evidence": "osv:CVE-2026-28732",
"products": [],
"severity": "medium",
"structured": {
"id": "CVE-2026-28732",
"aliases": [
"CVE-2026-28732",
"GHSA-wvcv-9xpm-7mqc",
"GO-2026-5726"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/mattermost/mattermost",
"type": "GIT",
"events": [
{
"introduced": "5b955468ea1ea8b56c0fb10feb258a36a767d7bb"
},
{
"fixed": "b21ef302025ee100f04f358c16301dc75fea91d9"
},
{
"introduced": "2a1ac98bd3fae587927adf9340ba266c8c02018e"
},
{
"fixed": "37b08cfe7154241c2c6a8af0fd500e0785bbc900"
},
{
"introduced": "9f2616376582893035a7e3cb38b0fab648bba4e8"
},
{
"fixed": "cc4ef6863ee114bc96be4e34478ec2f0db3eac4e"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "10.11.0"
},
{
"fixed": "10.11.14"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "11.4.0"
},
{
"fixed": "11.4.4"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "11.5.0"
},
{
"fixed": "11.5.2"
}
],
"source": "CPE_RANGE"
}
]
}
}
],
"versions": [
"v10.11.14-rc1",
"v11.5.0",
"v11.5.2-rc2",
"v11.5.2-rc1",
"v11.4.3",
"v10.11.13",
"v11.5.1",
"v10.11.13-rc1",
"v11.4.2",
"v10.11.12",
"v11.4.1-rc2",
"v11.4.1-rc1",
"v11.4.1",
"v10.11.11-rc2",
"v10.11.11",
"v11.4.0-rc3",
"v11.4.0",
"mattermost-redux@11.4.0",
"@mattermost/types@11.4.0",
"@mattermost/client@11.4.0",
"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-2026-28732.json"
}
}
],
"modified": "2026-10-28T02:30:52.766538470Z",
"provider": "osv",
"references": [
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/28xxx/CVE-2026-28732.json",
"https://mattermost.com/security-updates",
"https://nvd.nist.gov/vuln/detail/CVE-2026-28732"
],
"provider_metadata": {
"cwe_ids": [
"CWE-863"
],
"cna_assigner": "Mattermost",
"unresolved_ranges": [
{
"extracted_events": [
{
"range": [
{
"introduced": "11.5.0"
},
{
"last_affected": "11.5.1"
},
{
"introduced": "10.11.0"
},
{
"last_affected": "10.11.13"
},
{
"introduced": "11.4.0"
},
{
"last_affected": "11.4.3"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StandardRange"
}
]
}
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/28xxx/CVE-2026-28732.json"
}
},
"related_cves": [
{
"value": "CVE-2026-28732",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 521797,
"published_at": "2026-05-18T08:35:40.393+00:00"
}