CVE-2026-43653 Overview
CVE-2026-43653 is a memory handling vulnerability affecting multiple Apple operating systems, including iOS, iPadOS, macOS, and tvOS. An attacker on the same local network as the target device can exploit improper memory handling to cause a denial-of-service condition. The flaw is categorized under [CWE-400] Uncontrolled Resource Consumption, indicating that crafted network traffic can exhaust system resources or destabilize the affected component. Apple addressed the issue with improved memory handling in iOS 18.7.9, iPadOS 18.7.9, iOS 26.5, iPadOS 26.5, macOS Sonoma 14.8.7, macOS Tahoe 26.5, and tvOS 26.5.
Critical Impact
A local network attacker can trigger denial-of-service on unpatched Apple devices without authentication or user interaction.
Affected Products
- Apple iOS and iPadOS prior to 18.7.9 and prior to 26.5
- Apple macOS Sonoma prior to 14.8.7 and macOS Tahoe prior to 26.5
- Apple tvOS prior to 26.5
Discovery Timeline
- 2026-05-11 - CVE-2026-43653 published to the National Vulnerability Database (NVD)
- 2026-05-13 - Last updated in NVD database
Technical Details for CVE-2026-43653
Vulnerability Analysis
The vulnerability stems from improper memory handling within a network-facing component shared across Apple's operating systems. An adjacent attacker on the same local network segment can send specially crafted traffic that the vulnerable component fails to process safely. The result is a denial-of-service affecting availability of the targeted device or service.
Apple's advisories describe the remediation as improved memory handling, indicating the original code path mismanaged buffers, allocations, or object lifetimes when parsing local network input. The CWE-400 classification points to uncontrolled resource consumption, where attacker-supplied input causes excessive memory or CPU use until the affected process or system becomes unresponsive.
Because the attack vector is local network rather than remote, exploitation requires the attacker to share a broadcast domain with the victim. This includes shared Wi-Fi networks, corporate LAN segments, and unsegmented guest networks. No privileges or user interaction are required.
Root Cause
The root cause is improper memory handling in a network-accessible service on Apple platforms. Apple's advisories do not disclose the specific component or function, but the fix addresses how the code allocates, accesses, or releases memory during processing of network input.
Attack Vector
An attacker positioned on the local network sends crafted packets to the targeted Apple device. The vulnerable code path processes the input without adequate safeguards, leading to resource exhaustion or process failure. Refer to the Apple Support Document 127110 and related advisories for vendor-supplied technical context.
Detection Methods for CVE-2026-43653
Indicators of Compromise
- Unexpected crashes, restarts, or hangs of network-related services on iOS, iPadOS, macOS, or tvOS devices
- Sudden loss of network responsiveness on Apple devices while other hosts on the same LAN remain reachable
- Repeated kernel or daemon crash logs referencing memory faults around the time of network anomalies
Detection Strategies
- Monitor endpoint crash reports and diagnostic logs on managed Apple devices for repeated faults in network-facing daemons
- Inspect network telemetry for anomalous broadcast, multicast, or unicast traffic patterns targeting Apple device ports
- Correlate device unavailability events with local network activity from unmanaged or untrusted hosts on the same segment
Monitoring Recommendations
- Centralize macOS unified logs and iOS MDM diagnostic feeds to identify repeat crashes across the fleet
- Enable wireless intrusion detection on enterprise Wi-Fi to flag unusual L2/L3 traffic toward Apple endpoints
- Track OS build versions through MDM inventory to confirm patched builds are deployed across iOS, iPadOS, macOS, and tvOS
How to Mitigate CVE-2026-43653
Immediate Actions Required
- Update affected devices to iOS 18.7.9, iPadOS 18.7.9, iOS 26.5, iPadOS 26.5, macOS Sonoma 14.8.7, macOS Tahoe 26.5, or tvOS 26.5
- Prioritize patching for devices that regularly connect to untrusted or shared Wi-Fi networks
- Audit MDM compliance policies to enforce minimum OS versions across managed Apple endpoints
Patch Information
Apple released fixes in iOS 18.7.9 and iPadOS 18.7.9, iOS 26.5 and iPadOS 26.5, macOS Sonoma 14.8.7, macOS Tahoe 26.5, and tvOS 26.5. Detailed advisories are available in Apple Support Document 127111, Apple Support Document 127115, Apple Support Document 127117, and Apple Support Document 127118.
Workarounds
- Restrict Apple devices to trusted networks until updates are applied, avoiding open or public Wi-Fi
- Enforce network segmentation so Apple endpoints do not share broadcast domains with unmanaged or BYOD hosts
- Disable or limit local network discovery features on tvOS and macOS where operationally feasible
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
