CVE-2017-18876: Github.com/mattermost/mattermost server Path Traversal Vulnerability
MODERATECVE-2017-18876 is a MODERATE path traversal 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 is vulnerable to path traversal when files are stored locally. 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-2017-18876 at a Glance
How to Fix CVE-2017-18876
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.
Upgrade github.com/mattermost/mattermost-server to 4.1.2-0.20171004201910-6be8113eb60cUpgrade github.com/mattermost/mattermost-server to 4.2.1-0.20171004194140-6d3cb2ce07fcUpgrade github.com/mattermost/mattermost-server to 4.3.0Run the following command in your project directory to verify that all resolved dependencies use the patched release:
inspect dependencies for github.com/mattermost/mattermost-serverHow to Check if You Are Affected
To determine whether your application is affected by CVE-2017-18876, inspect your project dependencies for Github.com/mattermost/mattermost server:
inspect dependencies for github.com/mattermost/mattermost-serverAnalyze 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
CVE-2017-18876 Affected Github.com/mattermost/mattermost server Versions
3 component(s)| 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-2017-18876?
Which Github.com/mattermost/mattermost server versions are affected?
What version fixes CVE-2017-18876?
Is github.com/mattermost/mattermost-server affected?
What CWE is associated with CVE-2017-18876?
How can I check Go dependencies for CVE-2017-18876?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-hjqh-j6rj-gh8q",
"modified" : "2025-12-04T17:45:50Z",
"published" : "2022-05-24T17:21:03Z",
"aliases" : [ "CVE-2017-18876" ],
"summary" : "Mattermost Server is vulnerable to Path Traversal when files are stored locally",
"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 test for the existence of an arbitrary file.",
"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-2017-18876"
}, {
"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" : "2025-12-04T17:45:50Z",
"nvd_published_at" : "2020-06-19T17:15:00Z"
}
}