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CVE-2023-2787

Status: ModifiedMedium (6.5)—

Mattermost fails to check channel membership when accessing message threads, allowing an attacker to access arbitrary posts by using the message threads API.

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

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2023-2787",
  "cveTags": [],
  "metrics": {
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        "ssvcData": {
          "id": "CVE-2023-2787",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2024-12-06T22:51:25.728878Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
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        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 6.5,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
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      },
      {
        "type": "Primary",
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  },
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            },
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              "version": "7.1.9"
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            }
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  ],
  "published": "2023-06-16T09:15:09.920",
  "references": [
    {
      "url": "https://mattermost.com/security-updates/",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "responsibledisclosure@mattermost.com"
    },
    {
      "url": "https://mattermost.com/security-updates/",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
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      "description": [
        {
          "lang": "en",
          "value": "CWE-862"
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    },
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
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          "lang": "en",
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  "descriptions": [
    {
      "lang": "en",
      "value": "Mattermost fails to check channel membership when accessing message threads, allowing an attacker to access arbitrary posts by using the message threads API.\n\n"
    }
  ],
  "lastModified": "2026-06-17T05:53:26.423",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
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}