CVE-2020-9818VulnerabilityPublished 11/03/2021Updated 10/24/2026

CVE-2020-9818: Apple iOS, iPadOS, and watchOS Out-of-Bounds Write Vulnerability

Affects Apple iOS, iPadOS, and watchOSSource CISA KEV

Severity

High

No CVSS score published yet

Exploitation: Actively exploited – in CISA KEV since 11/03/2021
KEV deadline: 05/03/2022
EPSS: 2.3% chance of exploitation in 30 days – higher than 83% of CVEs

What to do

CISA required action

Apply updates per vendor instructions.

nvd.nist.gov/vuln/detail/CVE-2020-9818 (opens in a new tab)

Description

CVE-2020-9818 is an out-of-bounds write vulnerability in the Mail app on Apple iOS, iPadOS, and watchOS. This flaw may allow memory modification or cause the application to terminate when processing a specially crafted email message. The vulnerability has been exploited in the wild. No specific affected versions or patch information is provided in the available data.

Summary

Apple iOS, iPadOS, and watchOS Mail applications contain an out-of-bounds write vulnerability (CWE-787) that can be triggered by processing a maliciously crafted mail message. This vulnerability may lead to memory corruption or application termination. Exploitation in the wild has been reported, indicating active use by threat actors. The exact affected versions and patch status are not specified in the provided information.

Impact

Successful exploitation can result in memory modification or application termination, potentially leading to denial of service or other unintended behavior in the Mail app on affected Apple devices. The vulnerability has been exploited in the wild, demonstrating real-world impact.

Mitigation

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Users and administrators should monitor official Apple security updates and apply any relevant patches promptly once available.

Weaknesses

CWE-787Out-of-bounds Write (opens in a new tab)

What to do

Description

AnalysisAI-generated, updated 10/24/2026, 09:41:22 UTC

Weaknesses

References

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