CVE-2026-18795

Status: Undergoing AnalysisMedium (6.4)—

Severity6.4Medium · CVSS 3.1

Exploitation probability0.15 %higher than 4% of CVEs

Active exploitationNonot in the CISA catalog

Public exploitNot knownno public code found

Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to enforce DM/GM check on server side which allows an authenticated user to quarantine a post belonging to DM or GM via direct API call.. Mattermost Advisory ID: MMSA-2026-00756

CVSS

Base score: 6.4
Version: 3.1
Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:L

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 0.15 %
Percentile among all scored CVEs: 4
Score date: 10/21/2026

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).

ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

ExploitationT1210 Exploitation of Remote Serviceslateral movement85 %
Primary impactT1565 Data Manipulationimpact60 %

Usuario autenticado puede poner en cuarentena posts de DM/GM mediante llamada API directa por falta de comprobación en servidor (CWE-862); vector AV:N/PR:L/UI:N.

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

ATT&CK mitigations that cover these techniques

Network Segmentation Vulnerability Scanning Threat Intelligence Program Restrict File and Directory Permissions Privileged Account Management Remote Data Storage

Affected technologies (1)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

Mattermost — Mattermost^AI

CWEs

CWE-862

References

Show 1 references

https://mattermost.com/security-updates

Raw JSON (NVD)

Show

{
  "id": "CVE-2026-18795",
  "cveTags": [],
  "metrics": {
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        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-18795",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-10-16T11:59:31.276508Z"
        }
      }
    ],
    "cvssMetricV31": [
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        "cvssData": {
          "scope": "UNCHANGED",
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          "baseScore": 6.4,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:L",
          "integrityImpact": "LOW",
          "userInteraction": "NONE",
          "attackComplexity": "HIGH",
          "availabilityImpact": "LOW",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 4.7,
        "exploitabilityScore": 1.6
      }
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  "affected": [
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      "affectedData": [
        {
          "vendor": "Mattermost",
          "product": "Mattermost",
          "versions": [
            {
              "status": "affected",
              "version": "11.10.0",
              "versionType": "semver",
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            },
            {
              "status": "affected",
              "version": "11.7.0",
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            },
            {
              "status": "affected",
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            },
            {
              "status": "affected",
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            {
              "status": "unaffected",
              "version": "11.11.0"
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            {
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              "version": "11.10.1"
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            {
              "status": "unaffected",
              "version": "11.7.10"
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  "references": [
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      "source": "responsibledisclosure@mattermost.com"
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  "vulnStatus": "Undergoing Analysis",
  "weaknesses": [
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      "description": [
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    {
      "lang": "en",
      "value": "Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to enforce DM/GM check on server side which allows an authenticated user to quarantine a post belonging to DM or GM via direct API call.. Mattermost Advisory ID: MMSA-2026-00756"
    }
  ],
  "lastModified": "2026-10-16T19:23:18.623",
  "sourceIdentifier": "responsibledisclosure@mattermost.com"
}