CVE-2017-18917: Github.com/mattermost/mattermost server Mattermost Server Uses Weak Hashing Vulnerability

HIGH
Advisory Identifier: GHSA-jxc4-w54c-qv5r
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CWE-328
Published
Advisory Summary

CVE-2017-18917 is a HIGH mattermost server uses weak hashing vulnerability (CWE-328: Use of Weak Hash) affecting Github.com/mattermost/mattermost server libraries in the Go ecosystem. The issue involves mattermost server uses weak hashing for oauth, email verification tokens and invitations. Remediation is available by upgrading affected packages to version 3.7.5-0.20170421192444-247cd1e51a8c, 3.8.2.

CVE-2017-18917 at a Glance

CVE Identifier CVE-2017-18917
GHSA Identifier GHSA-jxc4-w54c-qv5r
Severity HIGH
CVSS v3.1 Base Score N/A
CWE Classification CWE-328: Use of Weak Hash
Affected Product Github.com/mattermost/mattermost server
Package Ecosystem Go
Published Date
Last Updated

How to Fix CVE-2017-18917

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: 3.7.5-0.20170421192444-247cd1e51a8c 
Upgrade github.com/mattermost/mattermost-server to 3.7.5-0.20170421192444-247cd1e51a8c
github.com/mattermost/mattermost-server fixed: 3.8.2 
Upgrade github.com/mattermost/mattermost-server to 3.8.2
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-2017-18917, 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 3.7.5-0.20170421192444-247cd1e51a8c), 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

An issue was discovered in Mattermost Server before 3.8.2 and 3.7.5. Weak hashing was used for e-mail invitations, OAuth, and e-mail verification tokens.

CVE-2017-18917 Affected Github.com/mattermost/mattermost server Versions

2 component(s)
Fixed Versions:
3.7.5-0.20170421192444-247cd1e51a8c3.8.2
Product / Package Ecosystem Affected Versions Fixed Version
github.com/mattermost/mattermost-server
golang/github.com/mattermost/mattermost-server
Go
< 3.7.5-0.20170421192444-247cd1e51a8c
3.7.5-0.20170421192444-247cd1e51a8c
github.com/mattermost/mattermost-server
golang/github.com/mattermost/mattermost-server
Go
≥ 3.8.0
< 3.8.2
3.8.2

References

NVD — CVE-2017-18917 NVD
https://nvd.nist.gov/vuln/detail/CVE-2017-18917
Security Fix Commit FIX COMMIT
https://github.com/mattermost/mattermost/commit/247cd1e51a8c943628dc650e87e794b06aad4c2b
Security Fix Commit FIX COMMIT
https://github.com/mattermost/mattermost/commit/b74e85653660525d351d090a1e1874ae933bcbc8
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-2017-18917?
CVE-2017-18917 is a security vulnerability in Github.com/mattermost/mattermost server involving Mattermost Server uses weak hashing for OAuth, email verification tokens and invitations under CWE-328: Use of Weak Hash.
Which Github.com/mattermost/mattermost server versions are affected?
Affected versions include releases prior to 3.7.5-0.20170421192444-247cd1e51a8c, 3.8.2 across affected packages: github.com/mattermost/mattermost-server.
What version fixes CVE-2017-18917?
Upgrading to 3.7.5-0.20170421192444-247cd1e51a8c, 3.8.2 (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 3.7.5-0.20170421192444-247cd1e51a8c, 3.8.2. Upgrade your dependency to 3.7.5-0.20170421192444-247cd1e51a8c, 3.8.2 or later.
What CWE is associated with CVE-2017-18917?
CVE-2017-18917 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-2017-18917?
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-jxc4-w54c-qv5r",
  "modified" : "2026-02-06T22:58:55Z",
  "published" : "2022-05-24T17:21:07Z",
  "aliases" : [ "CVE-2017-18917" ],
  "summary" : "Mattermost Server uses weak hashing for OAuth, email verification tokens and invitations",
  "details" : "An issue was discovered in Mattermost Server before 3.8.2 and 3.7.5. Weak hashing was used for e-mail invitations, OAuth, and e-mail verification tokens.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/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" : "3.7.5-0.20170421192444-247cd1e51a8c"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/mattermost/mattermost-server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.8.0"
      }, {
        "fixed" : "3.8.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2017-18917"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mattermost/mattermost/commit/247cd1e51a8c943628dc650e87e794b06aad4c2b"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mattermost/mattermost/commit/b74e85653660525d351d090a1e1874ae933bcbc8"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/mattermost/mattermost"
  }, {
    "type" : "WEB",
    "url" : "https://mattermost.com/security-updates"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-328" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-02-06T22:58:55Z",
    "nvd_published_at" : "2020-06-19T20:15:00Z"
  }
}