CVE-2025-11776: Github.com/mattermost/mattermost/server/v8 Mattermost Fails To Properly Restrict Vulnerability

MODERATE
Advisory Identifier: GHSA-j6gg-r5jc-47cm
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CVSS 4.3
CWE-863
Published
Advisory Summary

CVE-2025-11776 is a MODERATE (CVSS 4.3) mattermost fails to properly restrict vulnerability (CWE-863: Incorrect Authorization) affecting Github.com/mattermost/mattermost/server/v8 libraries in the Go ecosystem. The issue involves mattermost fails to properly restrict access to archived channel search api. Remediation is available by upgrading affected packages to version 8.0.0-20250815165020-c8d66301415d, 5.3.2-0.20250815165020-c8d66301415d.

CVE-2025-11776 at a Glance

CVE Identifier CVE-2025-11776
GHSA Identifier GHSA-j6gg-r5jc-47cm
Severity MODERATE
CVSS v3.1 Base Score 4.3
CWE Classification CWE-863: Incorrect Authorization
Affected Product Github.com/mattermost/mattermost/server/v8
Package Ecosystem Go
Published Date
Last Updated

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:L/I:N/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality Low (C:L)
Integrity None (I:N)
Availability None (A:N)

How to Fix CVE-2025-11776

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.

github.com/mattermost/mattermost/server/v8 fixed: 8.0.0-20250815165020-c8d66301415d 
Upgrade github.com/mattermost/mattermost/server/v8 to 8.0.0-20250815165020-c8d66301415d
github.com/mattermost/mattermost fixed: 5.3.2-0.20250815165020-c8d66301415d 
Upgrade github.com/mattermost/mattermost to 5.3.2-0.20250815165020-c8d66301415d
github.com/mattermost/mattermost-server fixed: 5.3.2-0.20250815165020-c8d66301415d 
Upgrade github.com/mattermost/mattermost-server to 5.3.2-0.20250815165020-c8d66301415d
github.com/mattermost/mattermost-server/v5 fixed: 5.3.2-0.20250815165020-c8d66301415d 
Upgrade github.com/mattermost/mattermost-server/v5 to 5.3.2-0.20250815165020-c8d66301415d
github.com/mattermost/mattermost-server/v6 fixed: 5.3.2-0.20250815165020-c8d66301415d 
Upgrade github.com/mattermost/mattermost-server/v6 to 5.3.2-0.20250815165020-c8d66301415d
Verify Direct and Transitive Dependencies

Run 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/v8

How to Check if You Are Affected

To determine whether your application is affected by CVE-2025-11776, inspect your project dependencies for Github.com/mattermost/mattermost/server/v8:

inspect dependencies for github.com/mattermost/mattermost/server/v8

Analyze 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 8.0.0-20250815165020-c8d66301415d), 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

Mattermost versions < 11 fail to properly restrict access to archived channel search API which allows guest users to discover archived public channels via the `/api/v4/teams/{team_id}/channels/search_archived` endpoint

CVE-2025-11776 Affected Github.com/mattermost/mattermost/server/v8 Versions

5 component(s)
Fixed Versions:
8.0.0-20250815165020-c8d66301415d5.3.2-0.20250815165020-c8d66301415d
Product / Package Ecosystem Affected Versions Fixed Version
github.com/mattermost/mattermost/server/v8
golang/github.com/mattermost/mattermost/server/v8
Go
< 8.0.0-20250815165020-c8d66301415d
8.0.0-20250815165020-c8d66301415d
github.com/mattermost/mattermost
golang/github.com/mattermost/mattermost
Go
< 5.3.2-0.20250815165020-c8d66301415d
5.3.2-0.20250815165020-c8d66301415d
github.com/mattermost/mattermost-server
golang/github.com/mattermost/mattermost-server
Go
< 5.3.2-0.20250815165020-c8d66301415d
5.3.2-0.20250815165020-c8d66301415d
github.com/mattermost/mattermost-server/v5
golang/github.com/mattermost/mattermost-server/v5
Go
< 5.3.2-0.20250815165020-c8d66301415d
5.3.2-0.20250815165020-c8d66301415d
github.com/mattermost/mattermost-server/v6
golang/github.com/mattermost/mattermost-server/v6
Go
< 5.3.2-0.20250815165020-c8d66301415d
5.3.2-0.20250815165020-c8d66301415d

References

NVD — CVE-2025-11776 NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-11776
Github.com/mattermost/mattermost/server/v8 Security Information SECURITY
https://mattermost.com/security-updates
Security Fix Commit FIX COMMIT
https://github.com/mattermost/mattermost/commit/c8d66301415d5b447df0e829bdbaa92e8a83ecf8
github.com/mattermos... PACKAGE
github.com/mattermost/mattermost

Frequently Asked Questions

What is CVE-2025-11776?
CVE-2025-11776 is a security vulnerability in Github.com/mattermost/mattermost/server/v8 involving Mattermost fails to properly restrict access to archived channel search API under CWE-863: Incorrect Authorization.
Which Github.com/mattermost/mattermost/server/v8 versions are affected?
Affected versions include releases prior to 8.0.0-20250815165020-c8d66301415d, 5.3.2-0.20250815165020-c8d66301415d across affected packages: github.com/mattermost/mattermost/server/v8, github.com/mattermost/mattermost, github.com/mattermost/mattermost-server, github.com/mattermost/mattermost-server/v5, github.com/mattermost/mattermost-server/v6.
What version fixes CVE-2025-11776?
Upgrading to 8.0.0-20250815165020-c8d66301415d, 5.3.2-0.20250815165020-c8d66301415d (or the latest patched release for your respective branch) resolves the vulnerability.
Is github.com/mattermost/mattermost/server/v8 affected?
Yes, github.com/mattermost/mattermost/server/v8 is affected in releases prior to 8.0.0-20250815165020-c8d66301415d. Upgrade your dependency to 8.0.0-20250815165020-c8d66301415d or later.
Is github.com/mattermost/mattermost affected?
Yes, github.com/mattermost/mattermost is affected in releases prior to 5.3.2-0.20250815165020-c8d66301415d. Upgrade your dependency to 5.3.2-0.20250815165020-c8d66301415d or later.
What is the CVSS score of CVE-2025-11776?
CVE-2025-11776 has a CVSS v3.1 base score of 4.3 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.
What CWE is associated with CVE-2025-11776?
CVE-2025-11776 is classified under CWE-863: Incorrect Authorization (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.).
How can I check Go dependencies for CVE-2025-11776?
Run the dependency tree command: 'inspect dependencies for github.com/mattermost/mattermost/server/v8'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-j6gg-r5jc-47cm",
  "modified" : "2025-11-14T22:08:04Z",
  "published" : "2025-11-14T09:30:27Z",
  "aliases" : [ "CVE-2025-11776" ],
  "summary" : "Mattermost fails to properly restrict access to archived channel search API",
  "details" : "Mattermost versions < 11 fail to properly restrict access to archived channel search API which allows guest users to discover archived public channels via the `/api/v4/teams/{team_id}/channels/search_archived` endpoint",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/mattermost/mattermost/server/v8"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "8.0.0-20250815165020-c8d66301415d"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/mattermost/mattermost"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "5.3.2-0.20250815165020-c8d66301415d"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/mattermost/mattermost-server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "5.3.2-0.20250815165020-c8d66301415d"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/mattermost/mattermost-server/v5"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "5.3.2-0.20250815165020-c8d66301415d"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/mattermost/mattermost-server/v6"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "5.3.2-0.20250815165020-c8d66301415d"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-11776"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mattermost/mattermost/commit/c8d66301415d5b447df0e829bdbaa92e8a83ecf8"
  }, {
    "type" : "WEB",
    "url" : "https://mattermost.com/security-updates"
  }, {
    "type" : "PACKAGE",
    "url" : "github.com/mattermost/mattermost"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-863" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-11-14T22:08:04Z",
    "nvd_published_at" : "2025-11-14T08:15:43Z"
  }
}