CVE-2026-3115 (GCVE-0-2026-3115)

Vulnerability from cvelistv5 – Published: 2026-03-26 16:23 – Updated: 2026-03-26 17:51
VLAI?
Title
Guest users can view group member IDs without respecting view restrictions
Summary
Mattermost versions 11.2.x <= 11.2.2, 10.11.x <= 10.11.10, 11.4.x <= 11.4.0, 11.3.x <= 11.3.1 fail to apply view restrictions when retrieving group member IDs, which allows authenticated guest users to enumerate user IDs outside their allowed visibility scope via the group retrieval endpoint.. Mattermost Advisory ID: MMSA-2026-00594
Severity ?
4.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
CWE
  • CWE-863 - Incorrect Authorization
Assigner
References
Impacted products
Vendor Product Version
Mattermost Mattermost Affected: 11.2.0 , ≤ 11.2.2 (semver)
Affected: 10.11.0 , ≤ 10.11.10 (semver)
Affected: 11.4.0 , ≤ 11.4.0 (semver)
Affected: 11.3.0 , ≤ 11.3.1 (semver)
Unaffected: 11.5.0
Unaffected: 11.2.3
Unaffected: 10.11.11
Unaffected: 11.4.1
Unaffected: 11.3.2
Create a notification for this product.
Credits
winfunc
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-3115",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-03-26T17:37:24.982329Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-03-26T17:51:14.689Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Mattermost",
          "vendor": "Mattermost",
          "versions": [
            {
              "lessThanOrEqual": "11.2.2",
              "status": "affected",
              "version": "11.2.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "10.11.10",
              "status": "affected",
              "version": "10.11.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "11.4.0",
              "status": "affected",
              "version": "11.4.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "11.3.1",
              "status": "affected",
              "version": "11.3.0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "11.5.0"
            },
            {
              "status": "unaffected",
              "version": "11.2.3"
            },
            {
              "status": "unaffected",
              "version": "10.11.11"
            },
            {
              "status": "unaffected",
              "version": "11.4.1"
            },
            {
              "status": "unaffected",
              "version": "11.3.2"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "winfunc"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Mattermost versions 11.2.x \u003c= 11.2.2, 10.11.x \u003c= 10.11.10, 11.4.x \u003c= 11.4.0, 11.3.x \u003c= 11.3.1 fail to apply view restrictions when retrieving group member IDs, which allows authenticated guest users to enumerate user IDs outside their allowed visibility scope via the group retrieval endpoint.. Mattermost Advisory ID: MMSA-2026-00594"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 4.3,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "integrityImpact": "NONE",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-863",
              "description": "CWE-863: Incorrect Authorization",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-03-26T16:23:05.887Z",
        "orgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee",
        "shortName": "Mattermost"
      },
      "references": [
        {
          "name": "MMSA-2026-00594",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://mattermost.com/security-updates"
        }
      ],
      "solutions": [
        {
          "lang": "en",
          "value": "Update Mattermost to versions 11.5.0, 11.2.3, 10.11.11, 11.4.1, 11.3.2 or higher."
        }
      ],
      "source": {
        "advisory": "MMSA-2026-00594",
        "defect": [
          "https://mattermost.atlassian.net/browse/MM-67354"
        ],
        "discovery": "EXTERNAL"
      },
      "title": "Guest users can view group member IDs without respecting view restrictions",
      "x_generator": {
        "engine": "cvelib 1.8.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee",
    "assignerShortName": "Mattermost",
    "cveId": "CVE-2026-3115",
    "datePublished": "2026-03-26T16:23:05.887Z",
    "dateReserved": "2026-02-24T11:06:52.132Z",
    "dateUpdated": "2026-03-26T17:51:14.689Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-3115\",\"sourceIdentifier\":\"responsibledisclosure@mattermost.com\",\"published\":\"2026-03-26T17:16:42.660\",\"lastModified\":\"2026-03-30T19:40:01.770\",\"vulnStatus\":\"Analyzed\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"Mattermost versions 11.2.x \u003c= 11.2.2, 10.11.x \u003c= 10.11.10, 11.4.x \u003c= 11.4.0, 11.3.x \u003c= 11.3.1 fail to apply view restrictions when retrieving group member IDs, which allows authenticated guest users to enumerate user IDs outside their allowed visibility scope via the group retrieval endpoint.. Mattermost Advisory ID: MMSA-2026-00594\"},{\"lang\":\"es\",\"value\":\"Las versiones de Mattermost 11.2.x \u0026lt;= 11.2.2, 10.11.x \u0026lt;= 10.11.10, 11.4.x \u0026lt;= 11.4.0, 11.3.x \u0026lt;= 11.3.1 no aplican las restricciones de visualizaci\u00f3n al recuperar los IDs de miembros de grupo, lo que permite a los usuarios invitados autenticados enumerar los IDs de usuario fuera de su \u00e1mbito de visibilidad permitido a trav\u00e9s del endpoint de recuperaci\u00f3n de grupo. ID de Aviso de Mattermost: MMSA-2026-00594\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"responsibledisclosure@mattermost.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N\",\"baseScore\":4.3,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"LOW\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":2.8,\"impactScore\":1.4}]},\"weaknesses\":[{\"source\":\"responsibledisclosure@mattermost.com\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-863\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"10.11.0\",\"versionEndExcluding\":\"10.11.11\",\"matchCriteriaId\":\"B6E5F368-358C-429B-8F04-3C8DF4A71A91\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"11.2.0\",\"versionEndExcluding\":\"11.2.3\",\"matchCriteriaId\":\"7F64C167-943D-4F3F-9374-BCC8DECB3881\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"11.3.0\",\"versionEndExcluding\":\"11.3.2\",\"matchCriteriaId\":\"805ECFFC-82FD-4754-AF95-32167E1D41CB\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:mattermost:mattermost_server:11.4.0:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"7B6A1FE2-D980-4755-A838-190A53A4D62B\"}]}]}],\"references\":[{\"url\":\"https://mattermost.com/security-updates\",\"source\":\"responsibledisclosure@mattermost.com\",\"tags\":[\"Vendor Advisory\"]}]}}",
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-3115\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-03-26T17:37:24.982329Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-03-26T17:47:18.656Z\"}}], \"cna\": {\"title\": \"Guest users can view group member IDs without respecting view restrictions\", \"source\": {\"defect\": [\"https://mattermost.atlassian.net/browse/MM-67354\"], \"advisory\": \"MMSA-2026-00594\", \"discovery\": \"EXTERNAL\"}, \"credits\": [{\"lang\": \"en\", \"type\": \"finder\", \"value\": \"winfunc\"}], \"metrics\": [{\"format\": \"CVSS\", \"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 4.3, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"MEDIUM\", \"vectorString\": \"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N\", \"integrityImpact\": \"NONE\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"NONE\", \"privilegesRequired\": \"LOW\", \"confidentialityImpact\": \"LOW\"}, \"scenarios\": [{\"lang\": \"en\", \"value\": \"GENERAL\"}]}], \"affected\": [{\"vendor\": \"Mattermost\", \"product\": \"Mattermost\", \"versions\": [{\"status\": \"affected\", \"version\": \"11.2.0\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"11.2.2\"}, {\"status\": \"affected\", \"version\": \"10.11.0\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"10.11.10\"}, {\"status\": \"affected\", \"version\": \"11.4.0\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"11.4.0\"}, {\"status\": \"affected\", \"version\": \"11.3.0\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"11.3.1\"}, {\"status\": \"unaffected\", \"version\": \"11.5.0\"}, {\"status\": \"unaffected\", \"version\": \"11.2.3\"}, {\"status\": \"unaffected\", \"version\": \"10.11.11\"}, {\"status\": \"unaffected\", \"version\": \"11.4.1\"}, {\"status\": \"unaffected\", \"version\": \"11.3.2\"}], \"defaultStatus\": \"unaffected\"}], \"solutions\": [{\"lang\": \"en\", \"value\": \"Update Mattermost to versions 11.5.0, 11.2.3, 10.11.11, 11.4.1, 11.3.2 or higher.\"}], \"references\": [{\"url\": \"https://mattermost.com/security-updates\", \"name\": \"MMSA-2026-00594\", \"tags\": [\"vendor-advisory\"]}], \"x_generator\": {\"engine\": \"cvelib 1.8.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"Mattermost versions 11.2.x \u003c= 11.2.2, 10.11.x \u003c= 10.11.10, 11.4.x \u003c= 11.4.0, 11.3.x \u003c= 11.3.1 fail to apply view restrictions when retrieving group member IDs, which allows authenticated guest users to enumerate user IDs outside their allowed visibility scope via the group retrieval endpoint.. Mattermost Advisory ID: MMSA-2026-00594\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-863\", \"description\": \"CWE-863: Incorrect Authorization\"}]}], \"providerMetadata\": {\"orgId\": \"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee\", \"shortName\": \"Mattermost\", \"dateUpdated\": \"2026-03-26T16:23:05.887Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-3115\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-03-26T17:51:14.689Z\", \"dateReserved\": \"2026-02-24T11:06:52.132Z\", \"assignerOrgId\": \"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee\", \"datePublished\": \"2026-03-26T16:23:05.887Z\", \"assignerShortName\": \"Mattermost\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




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.