What’s Vulnerable › Vulnerabilities

CVE-2023-40440

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2023-09-12 · updated 2026-06-17

Description

This issue was addressed with improved state management of S/MIME encrypted emails. This issue is fixed in macOS Monterey 12.6.8. A S/MIME encrypted email may be inadvertently sent unencrypted.

Affected products

• Apple macOS: from 12.0.0 before 12.6.8 — fixed in 12.6.8

How to fix

Upgrade to a fixed version: Apple macOS 12.6.8. Check the vendor advisory for mitigations.

References

• https://blog.aegrel.ee/apple-mail-smime.html
• https://support.apple.com/en-us/HT213844
• https://blog.aegrel.ee/apple-mail-smime.html
• https://support.apple.com/en-us/HT213844

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