Vulnerability-Lookup

GHSA-3C9R-7F29-QP32

Vulnerability from github – Published: 2026-02-16 12:30 – Updated: 2026-02-19 19:34

Summary

Mattermost fails to properly validate login method restrictions

Details

Mattermost versions 11.1.x <= 11.1.2, 10.11.x <= 10.11.9, 11.2.x <= 11.2.1 fail to properly validate login method restrictions which allows an authenticated user to bypass SSO-only login requirements via userID-based authentication. Mattermost Advisory ID: MMSA-2025-00548

Severity ?

5.4 (Medium)


                  
                    CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

Show details on source website

JSON

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/mattermost/mattermost/server/v8"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "8.0.0-20251212052346-61651b0df7ea"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c 11.1.3"
      },
      "package": {
        "ecosystem": "Go",
        "name": "github.com/mattermost/mattermost-server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "11.1.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c 10.11.10"
      },
      "package": {
        "ecosystem": "Go",
        "name": "github.com/mattermost/mattermost-server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "10.11.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c 11.2.2"
      },
      "package": {
        "ecosystem": "Go",
        "name": "github.com/mattermost/mattermost-server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "11.2.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/mattermost/mattermost-server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "5.3.2-0.20251212052346-61651b0df7ea"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-0999"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-303"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-02-19T19:34:56Z",
    "nvd_published_at": "2026-02-16T10:16:08Z",
    "severity": "MODERATE"
  },
  "details": "Mattermost versions 11.1.x \u003c= 11.1.2, 10.11.x \u003c= 10.11.9, 11.2.x \u003c= 11.2.1 fail to properly validate login method restrictions which allows an authenticated user to bypass SSO-only login requirements via userID-based authentication. Mattermost Advisory ID: MMSA-2025-00548",
  "id": "GHSA-3c9r-7f29-qp32",
  "modified": "2026-02-19T19:34:56Z",
  "published": "2026-02-16T12:30:24Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-0999"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mattermost/mattermost/commit/61651b0df7ea5db55d1e54f8d6fb5fce4149309c"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/mattermost/mattermost"
    },
    {
      "type": "WEB",
      "url": "https://mattermost.com/security-updates"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Mattermost fails to properly validate login method restrictions"
}

CVE-2026-0999 (GCVE-0-2026-0999)

Vulnerability from cvelistv5 – Published: 2026-02-16 09:47 – Updated: 2026-02-17 16:53

Title

Authentication bypass via userID login when email and username login are disabled

Summary

Severity ?

5.4 (Medium)


                        
                          CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

CWE

CWE-303 - Incorrect Implementation of Authentication Algorithm

Assigner

Mattermost

References

URL

Tags

https://mattermost.com/security-updates

vendor-advisory

Impacted products

	Vendor	Product	Version
	Mattermost	Mattermost	Affected: 11.1.0 , ≤ 11.1.2 (semver) Affected: 10.11.0 , ≤ 10.11.9 (semver) Affected: 11.2.0 , ≤ 11.2.1 (semver) Unaffected: 11.3.0 Unaffected: 11.1.3 Unaffected: 10.11.10 Unaffected: 11.2.2

Credits

daw10

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-0999",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-02-17T16:52:58.796354Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-02-17T16:53:07.181Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Mattermost",
          "vendor": "Mattermost",
          "versions": [
            {
              "lessThanOrEqual": "11.1.2",
              "status": "affected",
              "version": "11.1.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "10.11.9",
              "status": "affected",
              "version": "10.11.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "11.2.1",
              "status": "affected",
              "version": "11.2.0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "11.3.0"
            },
            {
              "status": "unaffected",
              "version": "11.1.3"
            },
            {
              "status": "unaffected",
              "version": "10.11.10"
            },
            {
              "status": "unaffected",
              "version": "11.2.2"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "daw10"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Mattermost versions 11.1.x \u003c= 11.1.2, 10.11.x \u003c= 10.11.9, 11.2.x \u003c= 11.2.1 fail to properly validate login method restrictions which allows an authenticated user to bypass SSO-only login requirements via userID-based authentication. Mattermost Advisory ID: MMSA-2025-00548"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 5.4,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "integrityImpact": "LOW",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-303",
              "description": "CWE-303: Incorrect Implementation of Authentication Algorithm",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-02-16T09:47:45.960Z",
        "orgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee",
        "shortName": "Mattermost"
      },
      "references": [
        {
          "name": "MMSA-2025-00548",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://mattermost.com/security-updates"
        }
      ],
      "solutions": [
        {
          "lang": "en",
          "value": "Update Mattermost to versions 11.3.0, 11.1.3, 10.11.10, 11.2.2 or higher."
        }
      ],
      "source": {
        "advisory": "MMSA-2025-00548",
        "defect": [
          "https://mattermost.atlassian.net/browse/MM-66415"
        ],
        "discovery": "EXTERNAL"
      },
      "title": "Authentication bypass via userID login when email and username login are disabled"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee",
    "assignerShortName": "Mattermost",
    "cveId": "CVE-2026-0999",
    "datePublished": "2026-02-16T09:47:45.960Z",
    "dateReserved": "2026-01-15T15:59:41.357Z",
    "dateUpdated": "2026-02-17T16:53:07.181Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-3C9R-7F29-QP32

CVE-2026-0999 (GCVE-0-2026-0999)

Tags

Sightings

Nomenclature