What’s Vulnerable › Vulnerabilities

CVE-2021-30738

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-09-08 · updated 2026-06-17

Description

A malicious application may be able to overwrite arbitrary files. This issue is fixed in macOS Big Sur 11.4, Security Update 2021-004 Mojave. An issue with path validation logic for hardlinks was addressed with improved path sanitization.

Affected products

• macOS: from 10.14.0 through 10.14.5; 10.14.6, 10.14.6-security_update_2019-001, 10.14.6-security_update_2019-002, 10.14.6-security_update_2019-004, 10.14.6-security_update_2019-005, 10.14.6-security_update_2019-006 (+13)
• Apple macOS: from 11.0.1 before 11.4 — fixed in 11.4

How to fix

Upgrade to a fixed version: Apple macOS 11.4. Check the vendor advisory for mitigations.

References

• https://support.apple.com/en-us/HT212529
• https://support.apple.com/en-us/HT212531
• https://support.apple.com/en-us/HT212529
• https://support.apple.com/en-us/HT212531

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