CVE-2025-12756: Github.com/mattermost/mattermost/server/v8 Mattermost Fails To Validate User Vulnerability
MODERATECVE-2025-12756 is a MODERATE (CVSS 4.3) mattermost fails to validate user vulnerability (CWE-863: Incorrect Authorization) affecting Github.com/mattermost/mattermost/server/v8 libraries in the Go ecosystem. The issue involves mattermost fails to validate user permissions when deleting comments in boards. Remediation is available in the latest vendor maintenance releases.
CVE-2025-12756 at a Glance
Security Impact
CVSS: 4.3
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N).
How to Fix CVE-2025-12756
To remediate this vulnerability, upgrade all affected Github.com/mattermost/mattermost/server/v8 dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
Upgrade github.com/mattermost/mattermost/server/v8 to Latest secure releaseUpgrade github.com/mattermost/mattermost to Latest secure releaseUpgrade github.com/mattermost/mattermost to Latest secure releaseUpgrade github.com/mattermost/mattermost to Latest secure releaseUpgrade github.com/mattermost/mattermost to Latest secure releaseRun the following command in your project directory to verify that all resolved dependencies use the patched release:
inspect dependencies for github.com/mattermost/mattermost/server/v8How to Check if You Are Affected
To determine whether your application is affected by CVE-2025-12756, inspect your project dependencies for Github.com/mattermost/mattermost/server/v8:
inspect dependencies for github.com/mattermost/mattermost/server/v8Analyze the terminal output to locate any version of Github.com/mattermost/mattermost/server/v8 in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.
Note: Verify declared build manifests and deployed runtime container environments.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-863: Incorrect Authorization, where the product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check. In Github.com/mattermost/mattermost/server/v8, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2025-12756 Affected Github.com/mattermost/mattermost/server/v8 Versions
5 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
github.com/mattermost/mattermost/server/v8
|
Go |
≤ 8.0.0-20251013062617-7977e7e6dae3
|
|
|
github.com/mattermost/mattermost
|
Go |
≥ 10.11.0
≤ 10.11.4
|
|
|
github.com/mattermost/mattermost
|
Go |
≥ 10.12.0
≤ 10.12.1
|
|
|
github.com/mattermost/mattermost
|
Go |
≥ 10.5.0
≤ 10.5.12
|
|
|
github.com/mattermost/mattermost
|
Go |
≥ 11.0.0
≤ 11.0.2
|
|
References
Frequently Asked Questions
What is CVE-2025-12756?
Which Github.com/mattermost/mattermost/server/v8 versions are affected?
What version fixes CVE-2025-12756?
Is github.com/mattermost/mattermost/server/v8 affected?
Is github.com/mattermost/mattermost affected?
What is the CVSS score of CVE-2025-12756?
What CWE is associated with CVE-2025-12756?
How can I check Go dependencies for CVE-2025-12756?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-p6gj-jc38-x2m7",
"modified" : "2025-12-02T16:53:35Z",
"published" : "2025-12-01T21:30:26Z",
"aliases" : [ "CVE-2025-12756" ],
"summary" : "Mattermost fails to validate user permissions when deleting comments in Boards",
"details" : "Mattermost versions 11.0.x <= 11.0.2, 10.12.x <= 10.12.1, 10.11.x <= 10.11.4, 10.5.x <= 10.5.12 fail to validate user permissions when deleting comments in Boards, which allows an authenticated user with the editor role to delete comments created by other users.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Go",
"name" : "github.com/mattermost/mattermost/server/v8"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"last_affected" : "8.0.0-20251013062617-7977e7e6dae3"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Go",
"name" : "github.com/mattermost/mattermost"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "10.11.0"
}, {
"last_affected" : "10.11.4"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Go",
"name" : "github.com/mattermost/mattermost"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "10.12.0"
}, {
"last_affected" : "10.12.1"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Go",
"name" : "github.com/mattermost/mattermost"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "10.5.0"
}, {
"last_affected" : "10.5.12"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Go",
"name" : "github.com/mattermost/mattermost"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "11.0.0"
}, {
"last_affected" : "11.0.2"
} ]
} ]
} ],
"references" : [ {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-12756"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/mattermost/mattermost"
}, {
"type" : "WEB",
"url" : "https://mattermost.com/security-updates"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-863" ],
"severity" : "MODERATE",
"github_reviewed" : true,
"github_reviewed_at" : "2025-12-02T16:53:35Z",
"nvd_published_at" : "2025-12-01T20:15:49Z"
}
}