Mattermost doesn't validate channel ownership of an existing subscription before applying edits
Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x <= 10.11.17 Fail to validate channel ownership of an existing subscription before applying edits which allows an authenticated attacker to hijack subscriptions from channels they have no access to via a crafted PUT request to the subscription edit endpoint.. Mattermost Advisory ID: MMSA-2026-00650
GHSA-mxq2-5jpg-7474
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: osv:GHSA-mxq2-5jpg-7474
github.com/mattermost/mattermost-server
Source reference: /affected/0/package/name
- Affected versions
- Not stated in this record
- Fixed versions
- 11.7.1
Source reference:
/affected/0/ranges - Prerequisites
- Not stated in this record
github.com/mattermost/mattermost-server
Source reference: /affected/1/package/name
- Affected versions
- Not stated in this record
- Fixed versions
- 11.6.3
Source reference:
/affected/1/ranges - Prerequisites
- Not stated in this record
github.com/mattermost/mattermost-server
Source reference: /affected/2/package/name
- Affected versions
- Not stated in this record
- Fixed versions
- 11.5.6
Source reference:
/affected/2/ranges - Prerequisites
- Not stated in this record
github.com/mattermost/mattermost-server
Source reference: /affected/3/package/name
- Affected versions
- Not stated in this record
- Fixed versions
- 10.11.18
Source reference:
/affected/3/ranges - Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"ranges": [
{
"type": "SEMVER",
"events": [
{
"introduced": "11.7.0"
},
{
"fixed": "11.7.1"
}
]
}
],
"package": {
"name": "github.com/mattermost/mattermost-server",
"purl": "pkg:golang/github.com/mattermost/mattermost-server",
"ecosystem": "Go"
},
"database_specific": {
"source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-mxq2-5jpg-7474/GHSA-mxq2-5jpg-7474.json"
}
},
{
"ranges": [
{
"type": "SEMVER",
"events": [
{
"introduced": "11.6.0"
},
{
"fixed": "11.6.3"
}
]
}
],
"package": {
"name": "github.com/mattermost/mattermost-server",
"purl": "pkg:golang/github.com/mattermost/mattermost-server",
"ecosystem": "Go"
},
"database_specific": {
"source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-mxq2-5jpg-7474/GHSA-mxq2-5jpg-7474.json"
}
},
{
"ranges": [
{
"type": "SEMVER",
"events": [
{
"introduced": "11.5.0"
},
{
"fixed": "11.5.6"
}
]
}
],
"package": {
"name": "github.com/mattermost/mattermost-server",
"purl": "pkg:golang/github.com/mattermost/mattermost-server",
"ecosystem": "Go"
},
"database_specific": {
"source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-mxq2-5jpg-7474/GHSA-mxq2-5jpg-7474.json"
}
},
{
"ranges": [
{
"type": "SEMVER",
"events": [
{
"introduced": "10.11.0"
},
{
"fixed": "10.11.18"
}
]
}
],
"package": {
"name": "github.com/mattermost/mattermost-server",
"purl": "pkg:golang/github.com/mattermost/mattermost-server",
"ecosystem": "Go"
},
"database_specific": {
"source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-mxq2-5jpg-7474/GHSA-mxq2-5jpg-7474.json"
}
}
]- Related CVEs
- CVE-2026-6062
Source reference:
/aliases
Publisher severity
No explicit severity was provided.
- Event
- #23398 · Revision 1
- Added to Heist Feed
- Publisher date