Unbounded Request Body Read in MS Teams Plugin {{/changes}} Webhook Endpoint

Mattermost Plugins versions <=2.1.3.0 fail to limit the request body size on the {{/changes}} webhook endpoint which allows an authenticated attacker to cause memory exhaustion and denial of service via sending an oversized JSON payload. Mattermost Advisory ID: MMSA-2026-00611

Problem type

CWE-770: Allocation of Resources Without Limits or Throttling

Affected products

Mattermost

Mattermost

<= 2.1.3 - AFFECTED

2.3.2.0 - UNAFFECTED

References

MMSA-2026-00611

https://mattermost.com/security-updates

vendor-advisory

JSON source

https://cveawg.mitre.org/api/cve/CVE-2026-24661

Click to expand

{
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "cveMetadata": {
    "cveId": "CVE-2026-24661",
    "assignerOrgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee",
    "assignerShortName": "Mattermost",
    "dateUpdated": "2026-04-09T11:44:35.023Z",
    "dateReserved": "2026-02-11T20:56:06.566Z",
    "datePublished": "2026-04-09T10:12:45.340Z",
    "state": "PUBLISHED"
  },
  "containers": {
    "cna": {
      "providerMetadata": {
        "orgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee",
        "shortName": "Mattermost",
        "dateUpdated": "2026-04-09T10:12:45.340Z"
      },
      "title": "Unbounded Request Body Read in MS Teams Plugin {{/changes}} Webhook Endpoint",
      "descriptions": [
        {
          "lang": "en",
          "value": "Mattermost Plugins versions <=2.1.3.0 fail to limit the request body size on the {{/changes}} webhook endpoint which allows an authenticated attacker to cause memory exhaustion and denial of service via sending an oversized JSON payload. Mattermost Advisory ID: MMSA-2026-00611"
        }
      ],
      "affected": [
        {
          "vendor": "Mattermost",
          "product": "Mattermost",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "0",
              "status": "affected",
              "versionType": "semver",
              "lessThanOrEqual": "2.1.3"
            },
            {
              "version": "2.3.2.0",
              "status": "unaffected"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "lang": "en",
              "description": "CWE-770: Allocation of Resources Without Limits or Throttling",
              "cweId": "CWE-770",
              "type": "CWE"
            }
          ]
        }
      ],
      "references": [
        {
          "url": "https://mattermost.com/security-updates",
          "name": "MMSA-2026-00611",
          "tags": [
            "vendor-advisory"
          ]
        }
      ],
      "metrics": [
        {
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ],
          "cvssV3_1": {
            "version": "3.1",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L",
            "attackVector": "NETWORK",
            "attackComplexity": "HIGH",
            "privilegesRequired": "NONE",
            "userInteraction": "NONE",
            "scope": "UNCHANGED",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "availabilityImpact": "LOW",
            "baseScore": 3.7,
            "baseSeverity": "LOW"
          }
        }
      ],
      "solutions": [
        {
          "lang": "en",
          "value": "Update Mattermost Plugins to versions 2.3.2.0 or higher."
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "Lorenzo Gallegos",
          "type": "finder"
        }
      ]
    },
    "adp": [
      {
        "providerMetadata": {
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP",
          "dateUpdated": "2026-04-09T11:44:35.023Z"
        },
        "title": "CISA ADP Vulnrichment",
        "metrics": [
          {}
        ]
      }
    ]
  }
}