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CVE-2026-19600

Status: Undergoing AnalysisMedium (4.5)—
Severity4.5Medium · CVSS 3.1
Exploitation probability0.24 %higher than 14% of CVEs
Active exploitationNonot in the CISA catalog
Public exploitNot knownno public code found

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 sanitize authentication tokens before writing them to server log entries, which allows an attacker with access to server logs to obtain valid session tokens or OAuth access tokens and impersonate authenticated users via the debug-level Mattermost server log.. Mattermost Advisory ID: MMSA-2026-00763

CVSS

Base score
4.5
Version
3.1
Vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:N/A:N

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days
0.24 %
Percentile among all scored CVEs
14
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.

El vector exige interacción del usuario (UI:R) y privilegios altos (PR:H). El texto indica tokens de sesión y OAuth escritos en logs de depuración, que permiten suplantar usuarios.

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

AuditApplication Developer GuidanceUser TrainingRestrict Web-Based ContentRestrict File and Directory PermissionsPassword Policies

Affected technologies (1)

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

Mattermost — MattermostAI

CWEs

References

Show 1 references

Raw JSON (NVD)

Show
{
  "id": "CVE-2026-19600",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-19600",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-10-16T12:02:37.754353Z"
        }
      }
    ],
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      {
        "type": "Secondary",
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        "cvssData": {
          "scope": "UNCHANGED",
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          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:N/A:N",
          "integrityImpact": "NONE",
          "userInteraction": "REQUIRED",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "HIGH",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 0.9
      }
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      "affectedData": [
        {
          "vendor": "Mattermost",
          "product": "Mattermost",
          "versions": [
            {
              "status": "affected",
              "version": "11.9.0",
              "versionType": "semver",
              "lessThanOrEqual": "11.9.1"
            },
            {
              "status": "affected",
              "version": "11.8.0",
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            },
            {
              "status": "affected",
              "version": "11.7.0",
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              "status": "affected",
              "version": "11.10.0",
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            {
              "status": "unaffected",
              "version": "11.11.0"
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              "version": "11.9.2"
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            {
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              "version": "11.8.6"
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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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  "descriptions": [
    {
      "lang": "en",
      "value": "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 sanitize authentication tokens before writing them to server log entries, which allows an attacker with access to server logs to obtain valid session tokens or OAuth access tokens and impersonate authenticated users via the debug-level Mattermost server log.. Mattermost Advisory ID: MMSA-2026-00763"
    }
  ],
  "lastModified": "2026-10-16T19:23:18.623",
  "sourceIdentifier": "responsibledisclosure@mattermost.com"
}