CVE-2025-43510: Apple Multiple Products Improper Locking Vulnerability

CVE-2025-43510: Apple Improper Locking Flaw Added to CISA KEV

Apple has patched a high-severity improper locking vulnerability tracked as CVE-2025-43510, affecting a broad range of Apple operating systems including watchOS, iOS, iPadOS, macOS, visionOS, and tvOS. The U.S. Cybersecurity and Infrastructure Security Agency (CISA) added the flaw to its Known Exploited Vulnerabilities (KEV) Catalog on March 20, 2026, confirming active exploitation in the wild and mandating federal remediation by April 3, 2026.

The vulnerability allows a malicious application to cause unexpected changes in memory shared between processes — a class of attack rooted in race conditions and improper synchronization that can result in privilege escalation, data corruption, or code execution depending on the targeted memory region.

Vulnerability Details

Technical Analysis

Root Cause

The vulnerability is classified as CWE-667 (Improper Locking), which describes failures in the correct acquisition or release of lock objects when accessing shared resources. In this case, the flaw exists in how certain Apple OS kernels or system frameworks manage memory synchronization across process boundaries.

When two processes share a memory region and access to that region is not properly serialized through mutual exclusion primitives (locks, semaphores, or similar mechanisms), a malicious application can exploit the timing window between a lock check and the actual memory operation — a classic Time-of-Check to Time-of-Use (TOCTOU) race condition.

The attacker-controlled application is able to:

1. Trigger the race condition by scheduling writes to the shared memory region at the precise moment another process relies on the expected state
2. Corrupt shared memory contents before the victim process reads or acts on them
3. Escalate privileges or execute arbitrary operations depending on what the victim process does with the corrupted data

Apple confirmed the fix involved improved lock state checking throughout the affected code paths.

Attack Constraints

Affected Products & Fixed Versions

All devices running versions prior to the fixed releases listed above are considered affected. Devices that have applied the listed updates are protected.

CISA KEV Catalog Entry

CISA added CVE-2025-43510 to its KEV Catalog on March 20, 2026 as part of a batch of five newly added known-exploited vulnerabilities. The KEV entry confirms:

• Exploitation status: Yes — actively exploited in the wild
• Required action: Apply mitigations per vendor instructions (Apple security update) or discontinue use if mitigations are unavailable
• FCEB deadline: April 3, 2026 — Federal Civilian Executive Branch agencies must remediate by this date under Binding Operational Directive (BOD) 22-01

While BOD 22-01 mandates only apply to FCEB agencies, CISA strongly urges all organizations and individuals to apply the patches promptly given confirmed active exploitation.

Remediation

Update All Affected Devices Immediately

The only complete remediation is applying Apple's security updates:

iPhone & iPad:

Settings → General → Software Update → Download and Install

Mac:

System Settings → General → Software Update → Update Now

Apple Watch:

Watch app on iPhone → My Watch → General → Software Update

Apple TV:

Settings → System → Software Updates → Update Software

Apple Vision Pro:

Settings → General → Software Update

Interim Risk Reduction

If immediate patching is not possible:

1. Restrict App Store installations to apps from verified, trusted developers
2. Disable side-loading of untrusted applications (especially on enterprise MDM-managed devices)
3. Monitor device behavior for unexpected privilege escalation or anomalous inter-process communication
4. Prioritize update deployment via MDM for enterprise fleets — push the security update as a critical required update

Detection

Enterprise Monitoring

Security teams managing Apple device fleets should:

# Check enrolled device OS versions via MDM
# Identify devices still running vulnerable versions
# Example: Jamf Pro Smart Group query
# OS Version < 18.7.2 (iOS) OR OS Version < 14.8.2 (macOS Sonoma)

Indicators of Exploitation

Active exploitation of improper locking vulnerabilities often manifests as:

• Applications exhibiting unexpected elevated capabilities (accessing files or services outside their declared entitlements)
• Kernel panics or system instability triggered by specific apps
• Unusual inter-process memory access patterns in system logs
• Applications performing operations inconsistent with their stated function

Context: Apple KEV Additions

CVE-2025-43510 was one of five vulnerabilities CISA added to the KEV Catalog on March 20, 2026. The batch reflects an ongoing pattern of Apple platform vulnerabilities being actively exploited — often by sophisticated threat actors targeting iOS and macOS for espionage, surveillance, and persistent access campaigns.

The broad scope of affected platforms (six Apple operating systems) makes this update particularly important for enterprise environments operating mixed Apple device fleets.

Key Takeaways

1. CVE-2025-43510 is a CVSS 7.8 High improper locking flaw in Apple watchOS, iOS, iPadOS, macOS, visionOS, and tvOS — confirmed actively exploited
2. CISA added it to the KEV Catalog on March 20, 2026 with an April 3, 2026 remediation deadline for federal agencies
3. The vulnerability allows a malicious app to corrupt shared memory between processes, potentially enabling privilege escalation
4. Apply all pending Apple OS updates immediately — all affected devices are unprotected until updated
5. Enterprise teams should use MDM to enforce the security update across all enrolled Apple devices

Sources

• NVD — CVE-2025-43510
• CISA Adds Five Known Exploited Vulnerabilities to Catalog — March 20, 2026
• Apple Security Releases
• About the security content of macOS Tahoe 26.2 — Apple Support