CVE-2017-18891: Github.com/mattermost/mattermost server Mattermost Server Does Not Safeguard Vulnerability
MODERATECVE-2017-18891 is a MODERATE (CVSS 6.1) mattermost server does not safeguard vulnerability (General Security Weakness) affecting Github.com/mattermost/mattermost server libraries in the Go ecosystem. The issue involves mattermost server does not safeguard against phishing via error page links. Remediation is available by upgrading affected packages to version 4.0.5, 4.1.1, 4.2.0.
CVE-2017-18891 at a Glance
Security Impact
CVSS: 6.1
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N).
How to Fix CVE-2017-18891
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 4.0.5Upgrade github.com/mattermost/mattermost-server to 4.1.1Upgrade github.com/mattermost/mattermost-server to 4.2.0Run 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-2017-18891, 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 4.0.5), 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 General Security Weakness. 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-2017-18891 Affected Github.com/mattermost/mattermost server Versions
3 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
github.com/mattermost/mattermost-server
|
Go |
< 4.0.5
|
4.0.5
|
|
github.com/mattermost/mattermost-server
|
Go |
≥ 4.1.0
< 4.1.1
|
4.1.1
|
|
github.com/mattermost/mattermost-server
|
Go |
≥ 4.2.0-rc1
< 4.2.0
|
4.2.0
|
References
Frequently Asked Questions
What is CVE-2017-18891?
Which Github.com/mattermost/mattermost server versions are affected?
What version fixes CVE-2017-18891?
Is github.com/mattermost/mattermost-server affected?
What is the CVSS score of CVE-2017-18891?
What CWE is associated with CVE-2017-18891?
How can I check Go dependencies for CVE-2017-18891?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-vrh2-rprg-rgc6",
"modified" : "2026-01-12T18:16:42Z",
"published" : "2022-05-24T17:21:05Z",
"aliases" : [ "CVE-2017-18891" ],
"summary" : "Mattermost Server does not safeguard against phishing via error page links",
"details" : "An issue was discovered in Mattermost Server before 4.2.0, 4.1.1, and 4.0.5. It allows Phishing because an error page can have a link.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Go",
"name" : "github.com/mattermost/mattermost-server"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "4.0.5"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Go",
"name" : "github.com/mattermost/mattermost-server"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "4.1.0"
}, {
"fixed" : "4.1.1"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Go",
"name" : "github.com/mattermost/mattermost-server"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "4.2.0-rc1"
}, {
"fixed" : "4.2.0"
} ]
} ]
} ],
"references" : [ {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2017-18891"
}, {
"type" : "WEB",
"url" : "https://github.com/mattermost/mattermost/pull/7378"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/mattermost/mattermost"
}, {
"type" : "WEB",
"url" : "https://mattermost.com/security-updates"
} ],
"database_specific" : {
"cwe_ids" : [ ],
"severity" : "MODERATE",
"github_reviewed" : true,
"github_reviewed_at" : "2026-01-12T18:13:10Z",
"nvd_published_at" : "2020-06-19T19:15:00Z"
}
}