CVE-2017-18875: Github.com/mattermost/mattermost server Mattermost Server Does Not Prevent Vulnerability

MODERATE
Advisory Identifier: GHSA-9rr5-q43r-ccv4
CWE-22
Published
Advisory Summary

CVE-2017-18875 is a MODERATE mattermost server does not prevent vulnerability (CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')) affecting Github.com/mattermost/mattermost server libraries in the Go ecosystem. The issue involves mattermost server does not prevent system admin from arbitrary file creation. Remediation is available by upgrading affected packages to version 4.1.2-0.20171004201910-6be8113eb60c, 4.2.1-0.20171004194140-6d3cb2ce07fc, 4.3.0.

CVE-2017-18875 at a Glance

CVE Identifier CVE-2017-18875
GHSA Identifier GHSA-9rr5-q43r-ccv4
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Affected Product Github.com/mattermost/mattermost server
Package Ecosystem Go
Published Date
Last Updated

How to Fix CVE-2017-18875

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: 4.1.2-0.20171004201910-6be8113eb60c
Upgrade github.com/mattermost/mattermost-server to 4.1.2-0.20171004201910-6be8113eb60c
github.com/mattermost/mattermost-server fixed: 4.2.1-0.20171004194140-6d3cb2ce07fc
Upgrade github.com/mattermost/mattermost-server to 4.2.1-0.20171004194140-6d3cb2ce07fc
github.com/mattermost/mattermost-server fixed: 4.3.0
Upgrade github.com/mattermost/mattermost-server to 4.3.0
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-2017-18875, 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 4.1.2-0.20171004201910-6be8113eb60c), 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-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal'), where the product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. 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

An issue was discovered in Mattermost Server before 4.3.0, 4.2.1, and 4.1.2 when local storage for files is used. A System Admin can create arbitrary files.

CVE-2017-18875 Affected Github.com/mattermost/mattermost server Versions

3 component(s)
Fixed Versions:
4.1.2-0.20171004201910-6be8113eb60c4.2.1-0.20171004194140-6d3cb2ce07fc4.3.0
Product / Package Ecosystem Affected Versions Fixed Version
github.com/mattermost/mattermost-server
Go
< 4.1.2-0.20171004201910-6be8113eb60c
4.1.2-0.20171004201910-6be8113eb60c
github.com/mattermost/mattermost-server
Go
≥ 4.2.0-rc1.0.20171004154238-fadd9514f6e7
< 4.2.1-0.20171004194140-6d3cb2ce07fc
4.2.1-0.20171004194140-6d3cb2ce07fc
github.com/mattermost/mattermost-server
Go
≥ 4.3.0-rc1
< 4.3.0
4.3.0

References

Frequently Asked Questions

What is CVE-2017-18875?
CVE-2017-18875 is a security vulnerability in Github.com/mattermost/mattermost server involving Mattermost Server does not prevent System Admin from arbitrary file creation under CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal').
Which Github.com/mattermost/mattermost server versions are affected?
Affected versions include releases prior to 4.1.2-0.20171004201910-6be8113eb60c, 4.2.1-0.20171004194140-6d3cb2ce07fc, 4.3.0 across affected packages: github.com/mattermost/mattermost-server.
What version fixes CVE-2017-18875?
Upgrading to 4.1.2-0.20171004201910-6be8113eb60c, 4.2.1-0.20171004194140-6d3cb2ce07fc, 4.3.0 (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 4.1.2-0.20171004201910-6be8113eb60c, 4.2.1-0.20171004194140-6d3cb2ce07fc, 4.3.0. Upgrade your dependency to 4.1.2-0.20171004201910-6be8113eb60c, 4.2.1-0.20171004194140-6d3cb2ce07fc, 4.3.0 or later.
What CWE is associated with CVE-2017-18875?
CVE-2017-18875 is classified under CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') (The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.).
How can I check Go dependencies for CVE-2017-18875?
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
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-9rr5-q43r-ccv4",
  "modified" : "2025-12-04T17:45:46Z",
  "published" : "2022-05-24T17:21:03Z",
  "aliases" : [ "CVE-2017-18875" ],
  "summary" : "Mattermost Server does not prevent System Admin from arbitrary file creation",
  "details" : "An issue was discovered in Mattermost Server before 4.3.0, 4.2.1, and 4.1.2 when local storage for files is used. A System Admin can create arbitrary files.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/mattermost/mattermost-server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "4.1.2-0.20171004201910-6be8113eb60c"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/mattermost/mattermost-server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "4.2.0-rc1.0.20171004154238-fadd9514f6e7"
      }, {
        "fixed" : "4.2.1-0.20171004194140-6d3cb2ce07fc"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/mattermost/mattermost-server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "4.3.0-rc1"
      }, {
        "fixed" : "4.3.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2017-18875"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mattermost/mattermost/commit/6be8113eb60cf5ddd2dc1c3f4db05cae0c183086"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mattermost/mattermost/commit/6d3cb2ce07fc799832081e93843b405b390057fa"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mattermost/mattermost/commit/fadd9514f6e71590aba781a7035e1de4150137b0"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/mattermost/mattermost"
  }, {
    "type" : "WEB",
    "url" : "https://mattermost.com/security-updates"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-22" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-12-04T17:45:46Z",
    "nvd_published_at" : "2020-06-19T17:15:00Z"
  }
}