CVE-2017-18909: Github.com/mattermost/mattermost server Mattermost Server SAML Implementation Does Vulnerability

HIGH
Advisory Identifier: GHSA-r6j5-fqx9-7qv9
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CVSS 7.5
CWE-311 CWE-347
Published
Advisory Summary

CVE-2017-18909 is a HIGH (CVSS 7.5) mattermost server saml implementation does vulnerability (CWE-311: Missing Encryption of Sensitive Data) affecting Github.com/mattermost/mattermost server libraries in the Go ecosystem. The issue involves mattermost server saml implementation does not require encryption or signature verification as default. Remediation is available by upgrading affected packages to version 3.8.1-0.20170504181128-4f074fed0d65.

CVE-2017-18909 at a Glance

CVE Identifier CVE-2017-18909
GHSA Identifier GHSA-r6j5-fqx9-7qv9
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-311: Missing Encryption of Sensitive Data
Affected Product Github.com/mattermost/mattermost server
Package Ecosystem Go
Published Date
Last Updated

Security Impact

CVSS: 7.5

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:N/S:U/C:H/I:N/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity None (I:N)
Availability None (A:N)

How to Fix CVE-2017-18909

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: 3.8.1-0.20170504181128-4f074fed0d65 
Upgrade github.com/mattermost/mattermost-server to 3.8.1-0.20170504181128-4f074fed0d65
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-2017-18909, 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 3.8.1-0.20170504181128-4f074fed0d65), 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-311: Missing Encryption of Sensitive Data, where the product does not encrypt sensitive or critical information before storage or transmission. 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 3.9.0 when SAML is used. Encryption and signature verification are not mandatory.

CVE-2017-18909 Affected Github.com/mattermost/mattermost server Versions

1 component(s)
Fixed Versions:
3.8.1-0.20170504181128-4f074fed0d65
Product / Package Ecosystem Affected Versions Fixed Version
github.com/mattermost/mattermost-server
golang/github.com/mattermost/mattermost-server
Go
< 3.8.1-0.20170504181128-4f074fed0d65
3.8.1-0.20170504181128-4f074fed0d65

References

NVD — CVE-2017-18909 NVD
https://nvd.nist.gov/vuln/detail/CVE-2017-18909
Security Fix Commit FIX COMMIT
https://github.com/mattermost/mattermost/commit/4f074fed0d653a28779ac586e418341232d43e95
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-2017-18909?
CVE-2017-18909 is a security vulnerability in Github.com/mattermost/mattermost server involving Mattermost Server SAML implementation does not require encryption or signature verification as default under CWE-311: Missing Encryption of Sensitive Data.
Which Github.com/mattermost/mattermost server versions are affected?
Affected versions include releases prior to 3.8.1-0.20170504181128-4f074fed0d65 across affected packages: github.com/mattermost/mattermost-server.
What version fixes CVE-2017-18909?
Upgrading to 3.8.1-0.20170504181128-4f074fed0d65 (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 3.8.1-0.20170504181128-4f074fed0d65. Upgrade your dependency to 3.8.1-0.20170504181128-4f074fed0d65 or later.
What is the CVSS score of CVE-2017-18909?
CVE-2017-18909 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.
What CWE is associated with CVE-2017-18909?
CVE-2017-18909 is classified under CWE-311: Missing Encryption of Sensitive Data (The product does not encrypt sensitive or critical information before storage or transmission.).
How can I check Go dependencies for CVE-2017-18909?
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-r6j5-fqx9-7qv9",
  "modified" : "2026-02-10T14:16:28Z",
  "published" : "2022-05-24T17:21:06Z",
  "aliases" : [ "CVE-2017-18909" ],
  "summary" : "Mattermost Server SAML implementation does not require encryption or signature verification as default",
  "details" : "An issue was discovered in Mattermost Server before 3.9.0 when SAML is used. Encryption and signature verification are not mandatory.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/mattermost/mattermost-server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "3.8.1-0.20170504181128-4f074fed0d65"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2017-18909"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mattermost/mattermost/commit/4f074fed0d653a28779ac586e418341232d43e95"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/mattermost/mattermost"
  }, {
    "type" : "WEB",
    "url" : "https://mattermost.com/security-updates"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-311", "CWE-347" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-02-06T22:50:29Z",
    "nvd_published_at" : "2020-06-19T19:15:00Z"
  }
}