CVE intelligence and bounded remediation

CVE-2021-30857 — A race condition was addressed with improved locking

High CVSS 7.6

A race condition was addressed with improved locking. This issue is fixed in Security Update 2021-005 Catalina, iOS 14.8 and iPadOS 14.8, tvOS 15, iOS 15 and iPadOS 15, watchOS 8, macOS Big Sur 11.6. A malicious application may be able to execute arbitrary code with kernel privileges.

Severity
High
CVSS
7.6 (2.0)
Published
2021-08-24
CISA KEV
Not currently listed
Ecosystem
apple/platform
Weaknesses
CWE-362

Affected products

  • apple / ipados
  • apple / iphone_os
  • apple / mac_os_x
  • apple / mac_os_x / 10.15.7
  • apple / macos
  • apple / tvos

Showing 6 representative product identities from 13 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Race condition, TOCTOU, and lifecycle synchronization

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Map concurrent actors, shared state, lock boundaries, signals, callbacks, retries, and check-then-use sequences in the affected path.
  • Determine whether untrusted users can influence timing, object names, filesystem state, or repeated state transitions.
  • Identify clustered and multi-process behavior that repository-local tests may not represent.

Remediate safely

  • Make the sensitive state transition atomic or protect it with a consistently ordered synchronization primitive.
  • Perform authorization and invariant checks on the same authoritative object and transaction used for the operation.
  • Use unique private resources, safe ownership transfer, and idempotent operations; add deterministic concurrency regression tests.

Authoritative sources

Complete CVE record and remediation plan

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