CVE-2025-9078: Github.com/mattermost/mattermost server Mattermost Makes Use Of Weak Vulnerability

MODERATE
Advisory Identifier: GHSA-9p92-x77w-9fw2
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CVSS 4.3
CWE-328
Published
Advisory Summary

CVE-2025-9078 is a MODERATE (CVSS 4.3) mattermost makes use of weak vulnerability (CWE-328: Use of Weak Hash) affecting Github.com/mattermost/mattermost server libraries in the Go ecosystem. The issue involves mattermost makes use of weak hash. Remediation is available by upgrading affected packages to version 10.8.4, 10.5.9, 9.11.18, 10.10.2, 10.9.4, 8.0.0-20250718075842-cd87e5c87737.

CVE-2025-9078 at a Glance

CVE Identifier CVE-2025-9078
GHSA Identifier GHSA-9p92-x77w-9fw2
Severity MODERATE
CVSS v3.1 Base Score 4.3
CWE Classification CWE-328: Use of Weak Hash
Affected Product Github.com/mattermost/mattermost server
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-2025-9078

To remediate this vulnerability, upgrade all affected Github.com/mattermost/mattermost server 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 fixed: 10.8.4 
Upgrade github.com/mattermost/mattermost-server to 10.8.4
github.com/mattermost/mattermost-server fixed: 10.5.9 
Upgrade github.com/mattermost/mattermost-server to 10.5.9
github.com/mattermost/mattermost-server fixed: 9.11.18 
Upgrade github.com/mattermost/mattermost-server to 9.11.18
github.com/mattermost/mattermost-server fixed: 10.10.2 
Upgrade github.com/mattermost/mattermost-server to 10.10.2
github.com/mattermost/mattermost-server fixed: 10.9.4 
Upgrade github.com/mattermost/mattermost-server to 10.9.4
github.com/mattermost/mattermost/server/v8 fixed: 8.0.0-20250718075842-cd87e5c87737 
Upgrade github.com/mattermost/mattermost/server/v8 to 8.0.0-20250718075842-cd87e5c87737
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

How to Check if You Are Affected

To determine whether your application is affected by CVE-2025-9078, inspect your project dependencies for Github.com/mattermost/mattermost server:

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

Analyze the terminal output to locate any version of Github.com/mattermost/mattermost server in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 10.8.4), 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-328: Use of Weak Hash, where the product uses an algorithm that produces a digest (output value) that does not meet security expectations for a hash function that allows an adversary to reasonably determine the original input (preimage attack), find another input that can produce the same hash (2nd preimage attack), or find multiple inputs that evaluate to the same hash (birthday attack). In Github.com/mattermost/mattermost server, 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 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.10.x <= 10.10.1, 10.9.x <= 10.9.3 fail to properly validate cache keys for link metadata which allows authenticated users to access unauthorized posts and poison link previews via hash collision attacks on FNV-1 hashing.

CVE-2025-9078 Affected Github.com/mattermost/mattermost server Versions

6 component(s)
Fixed Versions:
10.8.410.5.99.11.1810.10.210.9.48.0.0-20250718075842-cd87e5c87737
Product / Package Ecosystem Affected Versions Fixed Version
github.com/mattermost/mattermost-server
golang/github.com/mattermost/mattermost-server
Go
≥ 10.8.0
< 10.8.4
10.8.4
github.com/mattermost/mattermost-server
golang/github.com/mattermost/mattermost-server
Go
≥ 10.5.0
< 10.5.9
10.5.9
github.com/mattermost/mattermost-server
golang/github.com/mattermost/mattermost-server
Go
≥ 9.11.0
< 9.11.18
9.11.18
github.com/mattermost/mattermost-server
golang/github.com/mattermost/mattermost-server
Go
≥ 10.10.0
< 10.10.2
10.10.2
github.com/mattermost/mattermost-server
golang/github.com/mattermost/mattermost-server
Go
≥ 10.9.0
< 10.9.4
10.9.4
github.com/mattermost/mattermost/server/v8
golang/github.com/mattermost/mattermost/server/v8
Go
< 8.0.0-20250718075842-cd87e5c87737
8.0.0-20250718075842-cd87e5c87737

References

NVD — CVE-2025-9078 NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-9078
Security Fix Commit FIX COMMIT
https://github.com/mattermost/mattermost/commit/356880c8430b77a4a390c89d5a33f6928188d137
Security Fix Commit FIX COMMIT
https://github.com/mattermost/mattermost/commit/944ad5cdd9876ef61c78c8275906262a4118755a
Security Fix Commit FIX COMMIT
https://github.com/mattermost/mattermost/commit/a8a4badc130be101e5bc4b7916bbcd2f966c4b79
Security Fix Commit FIX COMMIT
https://github.com/mattermost/mattermost/commit/cd87e5c877373f109742aa90a3fa136c14774325
Github.com/mattermost/mattermost server Source Repository REPOSITORY
https://github.com/mattermost/mattermost
Github.com/mattermost/mattermost server Security Information SECURITY
https://mattermost.com/security-updates

Frequently Asked Questions

What is CVE-2025-9078?
CVE-2025-9078 is a security vulnerability in Github.com/mattermost/mattermost server involving Mattermost makes Use of Weak Hash under CWE-328: Use of Weak Hash.
Which Github.com/mattermost/mattermost server versions are affected?
Affected versions include releases prior to 10.8.4, 10.5.9, 9.11.18, 10.10.2, 10.9.4, 8.0.0-20250718075842-cd87e5c87737 across affected packages: github.com/mattermost/mattermost-server, github.com/mattermost/mattermost/server/v8.
What version fixes CVE-2025-9078?
Upgrading to 10.8.4, 10.5.9, 9.11.18, 10.10.2, 10.9.4, 8.0.0-20250718075842-cd87e5c87737 (or the latest patched release for your respective branch) resolves the vulnerability.
Is github.com/mattermost/mattermost-server affected?
Yes, github.com/mattermost/mattermost-server is affected in releases prior to 10.8.4, 10.5.9, 9.11.18, 10.10.2, 10.9.4. Upgrade your dependency to 10.8.4, 10.5.9, 9.11.18, 10.10.2, 10.9.4 or later.
Is github.com/mattermost/mattermost/server/v8 affected?
Yes, github.com/mattermost/mattermost/server/v8 is affected in releases prior to 8.0.0-20250718075842-cd87e5c87737. Upgrade your dependency to 8.0.0-20250718075842-cd87e5c87737 or later.
What is the CVSS score of CVE-2025-9078?
CVE-2025-9078 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-2025-9078?
CVE-2025-9078 is classified under CWE-328: Use of Weak Hash (The product uses an algorithm that produces a digest (output value) that does not meet security expectations for a hash function that allows an adversary to reasonably determine the original input (preimage attack), find another input that can produce the same hash (2nd preimage attack), or find multiple inputs that evaluate to the same hash (birthday attack).).
How can I check Go dependencies for CVE-2025-9078?
Run the dependency tree command: 'inspect dependencies for github.com/mattermost/mattermost-server'. 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-9p92-x77w-9fw2",
  "modified" : "2025-09-16T19:13:08Z",
  "published" : "2025-09-15T12:31:25Z",
  "aliases" : [ "CVE-2025-9078" ],
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  "severity" : [ {
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    },
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      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-9078"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mattermost/mattermost/commit/356880c8430b77a4a390c89d5a33f6928188d137"
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    "type" : "WEB",
    "url" : "https://github.com/mattermost/mattermost/commit/944ad5cdd9876ef61c78c8275906262a4118755a"
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    "url" : "https://github.com/mattermost/mattermost"
  }, {
    "type" : "WEB",
    "url" : "https://mattermost.com/security-updates"
  } ],
  "database_specific" : {
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    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-09-16T19:13:08Z",
    "nvd_published_at" : "2025-09-15T10:15:32Z"
  }
}