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CVE-2020-9818

Status: AnalyzedHigh (8.8)⚠ Active exploitation

An out-of-bounds write issue was addressed with improved bounds checking. This issue is fixed in iOS 13.5 and iPadOS 13.5, iOS 12.4.7, watchOS 6.2.5. Processing a maliciously crafted mail message may lead to unexpected memory modification or application termination.

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).

CISA KEV — actively exploited

🎯 ATT&CK techniques

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

Vector AV:N/UI:R requiere interacción (abrir correo malicioso). CWE-787 (out-of-bounds write) en procesamiento de mensajes permite RCE o crash. KEV activo y ransomware sugieren ejecución de código post-explotación.

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 ContentPrivileged Account ManagementLimit Software InstallationFilter Network TrafficExecution PreventionBehavior Prevention on Endpoint

Affected technologies (3)

Apple — IpadosApple — Iphone OSApple — Watchos

CWEs

References

Raw JSON (NVD)

Show
{
  "id": "CVE-2020-9818",
  "cveTags": [],
  "metrics": {
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          "options": [
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          "version": "2.0.3",
          "timestamp": "2025-08-19T00:00:00+00:00"
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    "cvssMetricV31": [
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  ],
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    {
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      "lang": "en",
      "value": "An out-of-bounds write issue was addressed with improved bounds checking. This issue is fixed in iOS 13.5 and iPadOS 13.5, iOS 12.4.7, watchOS 6.2.5. Processing a maliciously crafted mail message may lead to unexpected memory modification or application termination."
    },
    {
      "lang": "es",
      "value": "Se abordó un problema de escritura fuera de límites con una comprobación de límites mejorada. Este problema es corregido en iOS versión 13.5 y iPadOS versión 13.5, iOS 12.4.7, watchOS versión 6.2.5. El procesamiento de un mensaje de correo diseñado con fines maliciosos puede conllevar a modificaciones inesperadas de la memoria o la finalización de la aplicación"
    }
  ],
  "lastModified": "2026-06-17T03:28:37.607",
  "cisaActionDue": "2022-05-03",
  "cisaExploitAdd": "2021-11-03",
  "configurations": [
    {
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  "sourceIdentifier": "product-security@apple.com",
  "cisaRequiredAction": "Apply updates per vendor instructions.",
  "cisaVulnerabilityName": "Apple iOS, iPadOS, and watchOS Out-of-Bounds Write Vulnerability"
}