CVE-2026-43779 Overview
CVE-2026-43779 is a logic flaw in Apple macOS that allows an application to intercept network connections intended for another process. Apple addressed the issue with improved restrictions in macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, and macOS Tahoe 26.6. The weakness is categorized as improper access control [CWE-284]. Successful exploitation lets a local application receive traffic destined for a different, legitimate process on the same host. This creates conditions for credential capture, session interception, and man-in-the-middle style attacks against local services.
Critical Impact
A malicious application can intercept network traffic intended for another process, exposing credentials, session tokens, and sensitive application data.
Affected Products
- Apple macOS Sequoia (versions prior to 15.7.8)
- Apple macOS Sonoma (versions prior to 14.8.8)
- Apple macOS Tahoe (versions prior to 26.6)
Discovery Timeline
- 2026-07-27 - CVE-2026-43779 published to the National Vulnerability Database (NVD)
- 2026-07-28 - Last updated in NVD database
Technical Details for CVE-2026-43779
Vulnerability Analysis
The vulnerability stems from insufficient restrictions in macOS network binding and socket assignment logic. An application running on the system can claim or bind to a network resource that another process expects to own. As a result, inbound connections that should reach the legitimate service are routed to the attacker-controlled process instead.
Because the flaw involves improper access control [CWE-284] rather than memory corruption, exploitation does not require crafted payloads or complex primitives. Apple's advisories describe the fix as "improved restrictions," indicating the patched code now validates ownership or entitlements before allowing a process to receive traffic on a given endpoint.
The EPSS probability is 0.385% with a percentile of 31.29 as of 2026-07-30, reflecting no observed exploitation activity at publication.
Root Cause
The root cause is a logic error in how macOS arbitrates which process is entitled to receive network connections on a shared endpoint. The affected component fails to enforce sufficient checks before assigning inbound traffic to a requesting process. A local application can therefore satisfy the flawed check and claim traffic that belongs to another process.
Attack Vector
A local application on the target macOS host registers or binds to a network resource that another process legitimately owns. When remote or local clients initiate connections to that endpoint, the operating system delivers the traffic to the malicious application. The attacker can then log the data, respond with forged content, or proxy the traffic to the legitimate service to remain undetected.
No verified proof-of-concept code has been published. See the Apple Support Article #128067, Apple Support Article #128071, and Apple Support Article #128072 for vendor technical details.
Detection Methods for CVE-2026-43779
Indicators of Compromise
- Unexpected user-space processes bound to ports or network endpoints normally owned by system daemons or trusted applications.
- Duplicate or racing bind() and listen() activity against the same endpoint from unrelated processes.
- Unsigned or newly installed applications initiating network listeners shortly after execution.
Detection Strategies
- Baseline the set of processes that bind to sensitive local endpoints and alert when a new or unsigned binary claims one of those ports.
- Correlate macOS Endpoint Security framework events (ES_EVENT_TYPE_NOTIFY_UIPC_BIND, process exec) with network telemetry to identify processes intercepting traffic for another service.
- Hunt for applications that bind to loopback endpoints used by browsers, IDEs, or authentication helpers on developer and corporate endpoints.
Monitoring Recommendations
- Monitor macOS versions across the fleet and flag hosts still running builds earlier than 15.7.8, 14.8.8, or 26.6.
- Track network listener inventories over time and surface deltas for review.
- Alert on unsigned or ad-hoc signed binaries opening TCP or UDP listeners on the local machine.
How to Mitigate CVE-2026-43779
Immediate Actions Required
- Update all affected macOS hosts to macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, or macOS Tahoe 26.6 as applicable.
- Audit installed applications and remove software from untrusted publishers, especially recently installed listeners.
- Restrict user ability to install unsigned or non-App Store applications on managed endpoints.
Patch Information
Apple resolved CVE-2026-43779 by tightening restrictions on which process is permitted to receive network connections. Patched builds are macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, and macOS Tahoe 26.6. Deployment details are documented in Apple Support Article #128067, Apple Support Article #128071, and Apple Support Article #128072.
Workarounds
- No official workaround exists; applying the vendor patch is the only supported remediation.
- Enforce application allow-listing via Gatekeeper and MDM configuration profiles to reduce the risk of a malicious binary executing locally.
- Require sensitive local services to authenticate clients with mutual TLS or signed tokens so intercepted connections cannot be silently impersonated.
# Verify installed macOS build meets the patched version
sw_vers -productVersion
# Trigger the software update check on a managed endpoint
sudo softwareupdate --list
sudo softwareupdate --install --all --restart
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
