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CVE-2026-4646

Status: AnalyzedMedium (4.3)—

Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to validate user-supplied input in API request handlers which allows an authenticated attacker to crash the plugin process via a crafted HTTP request to the PR details endpoint.. Mattermost Advisory ID: MMSA-2026-00638

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Affected technologies (1)

Mattermost — Mattermost Server

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2026-4646",
  "cveTags": [],
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          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-05-22T12:13:12.291023Z"
        }
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        "source": "responsibledisclosure@mattermost.com",
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          "scope": "UNCHANGED",
          "version": "3.1",
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          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "LOW",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "NONE"
        },
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      "affectedData": [
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  "published": "2026-05-22T11:16:22.863",
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      "source": "responsibledisclosure@mattermost.com",
      "description": [
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          "lang": "en",
          "value": "CWE-1287"
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      "value": "Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to validate user-supplied input in API request handlers which allows an authenticated attacker to crash the plugin process via a crafted HTTP request to the PR details endpoint.. Mattermost Advisory ID: MMSA-2026-00638"
    },
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      "lang": "es",
      "value": "Las versiones de Mattermost 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 no validan la entrada proporcionada por el usuario en los manejadores de solicitudes de la API, lo que permite a un atacante autenticado bloquear el proceso del plugin a través de una solicitud HTTP manipulada al endpoint de detalles de PR. ID de Aviso de Mattermost: MMSA-2026-00638"
    }
  ],
  "lastModified": "2026-07-23T16:10:00.137",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
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