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CVE-2026-100522

Status: DeferredMedium (5.1)—

Cotonti through 1.0.0 contains a reflected cross-site scripting vulnerability in message.php where the lng parameter is not properly escaped before output in the confirmation dialog. Unauthenticated attackers can craft malicious links with script payloads in the lng parameter to execute arbitrary JavaScript in victim browser sessions.

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).

🎯 ATT&CK techniques

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

XSS reflejado en parámetro lng de message.php (CWE-79) ejecutable sin autenticación mediante enlace malicioso; impacto: ejecución JavaScript en navegador (T1059.007).

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

Restrict Web-Based ContentUser TrainingExecution PreventionBehavior Prevention on EndpointDisable or Remove Feature or ProgramApplication Isolation and Sandboxing

Affected technologies (1)

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

Cotonti — CotontiAI

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2026-100522",
  "cveTags": [],
  "metrics": {
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      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-100522",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-09-28T17:41:22.365924Z"
        }
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    "cvssMetricV31": [
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        "cvssData": {
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          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
          "integrityImpact": "LOW",
          "userInteraction": "REQUIRED",
          "attackComplexity": "LOW",
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          "privilegesRequired": "NONE",
          "confidentialityImpact": "LOW"
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        "exploitabilityScore": 2.8
      }
    ],
    "cvssMetricV40": [
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        "type": "Secondary",
        "source": "disclosure@vulncheck.com",
        "cvssData": {
          "Safety": "NOT_DEFINED",
          "version": "4.0",
          "Recovery": "NOT_DEFINED",
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          "Automatable": "NOT_DEFINED",
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "valueDensity": "NOT_DEFINED",
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          "vulnIntegrityImpact": "NONE",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
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          "vulnAvailabilityImpact": "NONE",
          "availabilityRequirement": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
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          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "vulnerabilityResponseEffort": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED"
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  "affected": [
    {
      "source": "disclosure@vulncheck.com",
      "affectedData": [
        {
          "repo": "https://github.com/Cotonti/Cotonti",
          "vendor": "Cotonti",
          "product": "Cotonti",
          "versions": [
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              "version": "0",
              "versionType": "custom",
              "lessThanOrEqual": "1.0.0"
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          ],
          "packageURL": "pkg:composer/cotonti/cotonti",
          "programFiles": [
            "message.php"
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  "published": "2026-09-26T01:17:00.700",
  "references": [
    {
      "url": "https://github.com/Cotonti/Cotonti",
      "source": "disclosure@vulncheck.com"
    },
    {
      "url": "https://github.com/Cotonti/Cotonti/blob/1.0.0/message.php",
      "source": "disclosure@vulncheck.com"
    },
    {
      "url": "https://github.com/Cotonti/Cotonti/issues/1907",
      "source": "disclosure@vulncheck.com"
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      "url": "https://github.com/Cotonti/Cotonti/pull/1908",
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      "description": [
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    {
      "lang": "en",
      "value": "Cotonti through 1.0.0 contains a reflected cross-site scripting vulnerability in message.php where the lng parameter is not properly escaped before output in the confirmation dialog. Unauthenticated attackers can craft malicious links with script payloads in the lng parameter to execute arbitrary JavaScript in victim browser sessions."
    }
  ],
  "lastModified": "2026-09-28T18:17:11.477",
  "sourceIdentifier": "disclosure@vulncheck.com"
}