CVE-2025-9084: Github.com/mattermost/mattermost/server/v8 Mattermost Open Redirect Vulnerability Vulnerability

Q: What is CVE-2025-9084?

CVE-2025-9084 is a security vulnerability in Github.com/mattermost/mattermost/server/v8 involving Mattermost Open Redirect vulnerability under CWE-601: URL Redirection to Untrusted Site ('Open Redirect').

Q: Which Github.com/mattermost/mattermost/server/v8 versions are affected?

Affected versions include releases prior to 8.0.0-202508080704-39bd251fe4f600, 10.5.10 across affected packages: github.com/mattermost/mattermost/server/v8, github.com/mattermost/mattermost-server.

Q: What version fixes CVE-2025-9084?

Upgrading to 8.0.0-202508080704-39bd251fe4f600, 10.5.10 (or the latest patched release for your respective branch) resolves the vulnerability.

Q: Is github.com/mattermost/mattermost/server/v8 affected?

Yes, github.com/mattermost/mattermost/server/v8 is affected in releases prior to 8.0.0-202508080704-39bd251fe4f600. Upgrade your dependency to 8.0.0-202508080704-39bd251fe4f600 or later.

Q: Is github.com/mattermost/mattermost-server affected?

Yes, github.com/mattermost/mattermost-server is affected in releases prior to 10.5.10. Upgrade your dependency to 10.5.10 or later.

Q: What is the CVSS score of CVE-2025-9084?

CVE-2025-9084 has a CVSS v3.1 base score of 3.1 (LOW) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N.

Q: What CWE is associated with CVE-2025-9084?

CVE-2025-9084 is classified under CWE-601: URL Redirection to Untrusted Site ('Open Redirect') (The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.).

Q: How can I check Go dependencies for CVE-2025-9084?

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.

LOW

Advisory Identifier: GHSA-hm95-jx66-g2gh

CVSS 3.1

CWE-601

Published 2025-09-15

Advisory Summary

CVE-2025-9084 is a LOW (CVSS 3.1) mattermost open redirect vulnerability vulnerability (CWE-601: URL Redirection to Untrusted Site ('Open Redirect')) affecting Github.com/mattermost/mattermost/server/v8 libraries in the Go ecosystem. The issue involves mattermost open redirect vulnerability. Remediation is available by upgrading affected packages to version 8.0.0-202508080704-39bd251fe4f600, 10.5.10.

CVE-2025-9084 at a Glance

CVE Identifier CVE-2025-9084

GHSA Identifier GHSA-hm95-jx66-g2gh

Severity LOW

CVSS v3.1 Base Score 3.1

CWE Classification CWE-601: URL Redirection to Untrusted Site ('Open Redirect')

Affected Product Github.com/mattermost/mattermost/server/v8

Package Ecosystem Go

Published Date 2025-09-15

Last Updated 2025-09-16

Security Impact

CVSS: 3.1

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N).

Attack Vector Network (AV:N)

Attack Complexity High (AC:H)

Privileges Required None (PR:N)

User Interaction Required (UI:R)

Scope Unchanged (S:U)

Confidentiality None (C:N)

Integrity Low (I:L)

Availability None (A:N)

How to Fix CVE-2025-9084

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: 8.0.0-202508080704-39bd251fe4f600

Upgrade github.com/mattermost/mattermost/server/v8 to 8.0.0-202508080704-39bd251fe4f600

github.com/mattermost/mattermost-server fixed: 10.5.10

Upgrade github.com/mattermost/mattermost-server to 10.5.10

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-2025-9084, 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 8.0.0-202508080704-39bd251fe4f600), 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-601: URL Redirection to Untrusted Site ('Open Redirect'), where the web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect. 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 10.5.x <= 10.5.9 fail to properly validate redirect URLs which allows attackers to redirect users to malicious sites via crafted OAuth login URLs.

CVE-2025-9084 Affected Github.com/mattermost/mattermost/server/v8 Versions

2 component(s)

Fixed Versions:

8.0.0-202508080704-39bd251fe4f60010.5.10

Product / Package	Ecosystem	Affected Versions	Fixed Version
github.com/mattermost/mattermost/server/v8 golang/github.com/mattermost/mattermost/server/v8	Go	< 8.0.0-202508080704-39bd251fe4f600	8.0.0-202508080704-39bd251fe4f600
github.com/mattermost/mattermost-server golang/github.com/mattermost/mattermost-server	Go	≥ 10.5.0 < 10.5.10	10.5.10

References

NVD — CVE-2025-9084 NVD

https://nvd.nist.gov/vuln/detail/CVE-2025-9084

Security Fix Commit FIX COMMIT

https://github.com/mattermost/mattermost/commit/39bd251fe4f66b7e847fc6d653221886347ff160

Github.com/mattermost/mattermost/server/v8 Source Repository REPOSITORY

https://github.com/mattermost/mattermost

Github.com/mattermost/mattermost/server/v8 Security Information SECURITY

https://mattermost.com/security-updates

Frequently Asked Questions

What is CVE-2025-9084?

CVE-2025-9084 is a security vulnerability in Github.com/mattermost/mattermost/server/v8 involving Mattermost Open Redirect vulnerability under CWE-601: URL Redirection to Untrusted Site ('Open Redirect').

Which Github.com/mattermost/mattermost/server/v8 versions are affected?

Affected versions include releases prior to 8.0.0-202508080704-39bd251fe4f600, 10.5.10 across affected packages: github.com/mattermost/mattermost/server/v8, github.com/mattermost/mattermost-server.

What version fixes CVE-2025-9084?

Upgrading to 8.0.0-202508080704-39bd251fe4f600, 10.5.10 (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 8.0.0-202508080704-39bd251fe4f600. Upgrade your dependency to 8.0.0-202508080704-39bd251fe4f600 or later.

Is github.com/mattermost/mattermost-server affected?

Yes, github.com/mattermost/mattermost-server is affected in releases prior to 10.5.10. Upgrade your dependency to 10.5.10 or later.

What is the CVSS score of CVE-2025-9084?

CVE-2025-9084 has a CVSS v3.1 base score of 3.1 (LOW) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N.

What CWE is associated with CVE-2025-9084?

CVE-2025-9084 is classified under CWE-601: URL Redirection to Untrusted Site ('Open Redirect') (The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.).

How can I check Go dependencies for CVE-2025-9084?

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-hm95-jx66-g2gh",
  "modified" : "2025-09-16T20:00:25Z",
  "published" : "2025-09-15T12:31:25Z",
  "aliases" : [ "CVE-2025-9084" ],
  "summary" : "Mattermost Open Redirect vulnerability",
  "details" : "Mattermost versions 10.5.x <= 10.5.9 fail to properly validate redirect URLs which allows attackers to redirect users to malicious sites via crafted OAuth login URLs.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/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"
      }, {
        "fixed" : "8.0.0-202508080704-39bd251fe4f600"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/mattermost/mattermost-server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "10.5.0"
      }, {
        "fixed" : "10.5.10"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-9084"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mattermost/mattermost/commit/39bd251fe4f66b7e847fc6d653221886347ff160"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/mattermost/mattermost"
  }, {
    "type" : "WEB",
    "url" : "https://mattermost.com/security-updates"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-601" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-09-16T20:00:25Z",
    "nvd_published_at" : "2025-09-15T11:15:34Z"
  }
}

CVSS V3

3.1 LOW