cvelistv5 - cve-2026-96259

CVE-2026-96259 (GCVE-0-2026-96259)

Vulnerability from cvelistv5

Published

2026-09-22 20:34

Modified

2026-09-23 13:10

Severity ?

5.5 (Medium) - CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N

CWE

CWE-918 - Server-Side Request Forgery (SSRF)

Summary

Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to apply the internal-connection filter to OAuth endpoint requests, which allows a System Administrator to make the server issue requests to internal network addresses and read the responses via the configured OAuth token and userinfo endpoints.. Mattermost Advisory ID: MMSA-2026-00776

References

URL

Tags

https://mattermost.com/security-updates

vendor-advisory

Impacted products

	Vendor	Product	Version
	Mattermost	Mattermost	Version: 11.9.0 ≤ 11.9.1 Version: 11.8.0 ≤ 11.8.5 Version: 11.7.0 ≤ 11.7.10 Version: 11.10.0 ≤ 11.10.1

Show details on NVD website

JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-96259",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-09-23T13:10:28.219588Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-09-23T13:10:47.754Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Mattermost",
          "vendor": "Mattermost",
          "versions": [
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              "lessThanOrEqual": "11.9.1",
              "status": "affected",
              "version": "11.9.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "11.8.5",
              "status": "affected",
              "version": "11.8.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "11.7.10",
              "status": "affected",
              "version": "11.7.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "11.10.1",
              "status": "affected",
              "version": "11.10.0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "11.11.0"
            },
            {
              "status": "unaffected",
              "version": "11.9.2"
            },
            {
              "status": "unaffected",
              "version": "11.8.6"
            },
            {
              "status": "unaffected",
              "version": "11.7.11"
            },
            {
              "status": "unaffected",
              "version": "11.10.2"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "n1nj4sec"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Mattermost versions 11.9.x \u003c= 11.9.1, 11.8.x \u003c= 11.8.5, 11.7.x \u003c= 11.7.10, 11.10.x \u003c= 11.10.1 fail to apply the internal-connection filter to OAuth endpoint requests, which allows a System Administrator to make the server issue requests to internal network addresses and read the responses via the configured OAuth token and userinfo endpoints.. Mattermost Advisory ID: MMSA-2026-00776"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 5.5,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "integrityImpact": "LOW",
            "privilegesRequired": "HIGH",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-918",
              "description": "CWE-918: Server-Side Request Forgery (SSRF)",
              "lang": "en",
              "type": "CWE"
            }
          ]
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      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-22T20:34:20.872Z",
        "orgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee",
        "shortName": "Mattermost"
      },
      "references": [
        {
          "name": "MMSA-2026-00776",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://mattermost.com/security-updates"
        }
      ],
      "solutions": [
        {
          "lang": "en",
          "value": "Update Mattermost to versions 11.11.0, 11.9.2, 11.8.6, 11.7.11, 11.10.2 or higher."
        }
      ],
      "source": {
        "advisory": "MMSA-2026-00776",
        "defect": [
          "https://mattermost.atlassian.net/browse/MM-70502"
        ],
        "discovery": "EXTERNAL"
      },
      "title": "Mattermost server-side request forgery via OAuth endpoints configurable by a System Administrator",
      "x_generator": {
        "engine": "cvelib 1.8.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee",
    "assignerShortName": "Mattermost",
    "cveId": "CVE-2026-96259",
    "datePublished": "2026-09-22T20:34:20.872Z",
    "dateReserved": "2026-09-22T19:59:57.887Z",
    "dateUpdated": "2026-09-23T13:10:47.754Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "vulnrichment": {
      "containers": "{\"cna\": {\"title\": \"Mattermost server-side request forgery via OAuth endpoints configurable by a System Administrator\", \"source\": {\"defect\": [\"https://mattermost.atlassian.net/browse/MM-70502\"], \"advisory\": \"MMSA-2026-00776\", \"discovery\": \"EXTERNAL\"}, \"credits\": [{\"lang\": \"en\", \"type\": \"finder\", \"value\": \"n1nj4sec\"}], \"metrics\": [{\"format\": \"CVSS\", \"cvssV3_1\": {\"scope\": \"CHANGED\", \"version\": \"3.1\", \"baseScore\": 5.5, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"MEDIUM\", \"vectorString\": \"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N\", \"integrityImpact\": \"LOW\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"NONE\", \"privilegesRequired\": \"HIGH\", \"confidentialityImpact\": \"LOW\"}, \"scenarios\": [{\"lang\": \"en\", \"value\": \"GENERAL\"}]}], \"affected\": [{\"vendor\": \"Mattermost\", \"product\": \"Mattermost\", \"versions\": [{\"status\": \"affected\", \"version\": \"11.9.0\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"11.9.1\"}, {\"status\": \"affected\", \"version\": \"11.8.0\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"11.8.5\"}, {\"status\": \"affected\", \"version\": \"11.7.0\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"11.7.10\"}, {\"status\": \"affected\", \"version\": \"11.10.0\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"11.10.1\"}, {\"status\": \"unaffected\", \"version\": \"11.11.0\"}, {\"status\": \"unaffected\", \"version\": \"11.9.2\"}, {\"status\": \"unaffected\", \"version\": \"11.8.6\"}, {\"status\": \"unaffected\", \"version\": \"11.7.11\"}, {\"status\": \"unaffected\", \"version\": \"11.10.2\"}], \"defaultStatus\": \"unaffected\"}], \"solutions\": [{\"lang\": \"en\", \"value\": \"Update Mattermost to versions 11.11.0, 11.9.2, 11.8.6, 11.7.11, 11.10.2 or higher.\"}], \"references\": [{\"url\": \"https://mattermost.com/security-updates\", \"name\": \"MMSA-2026-00776\", \"tags\": [\"vendor-advisory\"]}], \"x_generator\": {\"engine\": \"cvelib 1.8.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"Mattermost versions 11.9.x \u003c= 11.9.1, 11.8.x \u003c= 11.8.5, 11.7.x \u003c= 11.7.10, 11.10.x \u003c= 11.10.1 fail to apply the internal-connection filter to OAuth endpoint requests, which allows a System Administrator to make the server issue requests to internal network addresses and read the responses via the configured OAuth token and userinfo endpoints.. Mattermost Advisory ID: MMSA-2026-00776\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-918\", \"description\": \"CWE-918: Server-Side Request Forgery (SSRF)\"}]}], \"providerMetadata\": {\"orgId\": \"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee\", \"shortName\": \"Mattermost\", \"dateUpdated\": \"2026-09-22T20:34:20.872Z\"}}, \"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-96259\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-09-23T13:10:28.219588Z\"}}}], \"providerMetadata\": {\"shortName\": \"CISA-ADP\", \"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"dateUpdated\": \"2026-09-23T13:10:41.631Z\"}}]}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-96259\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-09-22T20:34:20.872Z\", \"dateReserved\": \"2026-09-22T19:59:57.887Z\", \"assignerOrgId\": \"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee\", \"datePublished\": \"2026-09-22T20:34:20.872Z\", \"assignerShortName\": \"Mattermost\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}

CERTFR-2026-AVI-1212

Vulnerability from certfr_avis

De multiples vulnérabilités ont été découvertes dans Mattermost Server. Elles permettent à un attaquant de provoquer un déni de service à distance et une atteinte à la confidentialité des données.

Solutions

Se référer au bulletin de sécurité de l'éditeur pour l'obtention des correctifs (cf. section Documentation).

Impacted products

Vendor	Product	Description
Mattermost	Mattermost Server	Mattermost Server versions 11.9.x antérieures à 11.9.2
Mattermost	Mattermost Server	Mattermost Server versions 11.7.x antérieures à 11.7.11
Mattermost	Mattermost Server	Mattermost Server versions 11.10.x antérieures à 11.10.2
Mattermost	Mattermost Server	Mattermost Server versions 11.8.x antérieures à 11.8.6

References

Title

Publication Time

Tags

Bulletin de sécurité Mattermost MMSA-2026-00775	2026-09-22	vendor-advisory
Bulletin de sécurité Mattermost MMSA-2026-00776	2026-09-22	vendor-advisory
Bulletin de sécurité Mattermost MMSA-2026-00771	2026-09-22	vendor-advisory

Show details on source website

JSON

To clipboard

{
  "$ref": "https://www.cert.ssi.gouv.fr/openapi.json",
  "affected_systems": [
    {
      "description": "Mattermost Server versions 11.9.x ant\u00e9rieures \u00e0 11.9.2",
      "product": {
        "name": "Mattermost Server",
        "vendor": {
          "name": "Mattermost",
          "scada": false
        }
      }
    },
    {
      "description": "Mattermost Server versions 11.7.x ant\u00e9rieures \u00e0 11.7.11",
      "product": {
        "name": "Mattermost Server",
        "vendor": {
          "name": "Mattermost",
          "scada": false
        }
      }
    },
    {
      "description": "Mattermost Server versions 11.10.x ant\u00e9rieures \u00e0 11.10.2",
      "product": {
        "name": "Mattermost Server",
        "vendor": {
          "name": "Mattermost",
          "scada": false
        }
      }
    },
    {
      "description": "Mattermost Server versions 11.8.x ant\u00e9rieures \u00e0 11.8.6",
      "product": {
        "name": "Mattermost Server",
        "vendor": {
          "name": "Mattermost",
          "scada": false
        }
      }
    }
  ],
  "affected_systems_content": "",
  "content": "## Solutions\n\nSe r\u00e9f\u00e9rer au bulletin de s\u00e9curit\u00e9 de l\u0027\u00e9diteur pour l\u0027obtention des correctifs (cf. section Documentation).",
  "cves": [
    {
      "name": "CVE-2026-96260",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-96260"
    },
    {
      "name": "CVE-2026-95666",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-95666"
    },
    {
      "name": "CVE-2026-96259",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-96259"
    }
  ],
  "initial_release_date": "2026-09-23T00:00:00",
  "last_revision_date": "2026-09-23T00:00:00",
  "links": [],
  "reference": "CERTFR-2026-AVI-1212",
  "revisions": [
    {
      "description": "Version initiale",
      "revision_date": "2026-09-23T00:00:00.000000"
    }
  ],
  "risks": [
    {
      "description": "D\u00e9ni de service \u00e0 distance"
    },
    {
      "description": "Atteinte \u00e0 la confidentialit\u00e9 des donn\u00e9es"
    }
  ],
  "summary": "De multiples vuln\u00e9rabilit\u00e9s ont \u00e9t\u00e9 d\u00e9couvertes dans Mattermost Server. Elles permettent \u00e0 un attaquant de provoquer un d\u00e9ni de service \u00e0 distance et une atteinte \u00e0 la confidentialit\u00e9 des donn\u00e9es.",
  "title": "Multiples vuln\u00e9rabilit\u00e9s dans Mattermost Server",
  "vendor_advisories": [
    {
      "published_at": "2026-09-22",
      "title": "Bulletin de s\u00e9curit\u00e9 Mattermost MMSA-2026-00775",
      "url": "https://mattermost.com/security-updates/"
    },
    {
      "published_at": "2026-09-22",
      "title": "Bulletin de s\u00e9curit\u00e9 Mattermost MMSA-2026-00776",
      "url": "https://mattermost.com/security-updates/"
    },
    {
      "published_at": "2026-09-22",
      "title": "Bulletin de s\u00e9curit\u00e9 Mattermost MMSA-2026-00771",
      "url": "https://mattermost.com/security-updates/"
    }
  ]
}

Sightings

Author	Source	Type	Date

Nomenclature

Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
Confirmed: The vulnerability is confirmed from an analyst perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
Patched: This vulnerability was successfully patched by the user reporting the sighting.
Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
Not confirmed: The user expresses doubt about the veracity of the vulnerability.
Not patched: This vulnerability was not successfully patched by the user reporting the sighting.

Action not permitted

CVE-2026-96259 (GCVE-0-2026-96259)

Vulnerability from cvelistv5

CERTFR-2026-AVI-1212

Vulnerability from certfr_avis

Solutions

Tags

Sightings

Nomenclature