CVE intelligence and bounded remediation

CVE-2021-30786 — A race condition was addressed with improved state handling

High CVSS 7

A race condition was addressed with improved state handling. This issue is fixed in iOS 14.7, macOS Big Sur 11.5. Opening a maliciously crafted PDF file may lead to an unexpected application termination or arbitrary code execution.

Severity
High
CVSS
7 (3.1)
Published
2021-09-08
CISA KEV
Not currently listed
Ecosystem
apple/platform
Weaknesses
CWE-362

Affected products

  • apple / iphone_os
  • apple / macos

Matched remediation archetype

Race condition, TOCTOU, and lifecycle synchronization

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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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