CVE-2026-47122 in Sparkle
Summary
by MITRE • 07/21/2026
Sparkle is a software update framework for macOS. In versions up to and including 2.9.1, `Autoupdate/AppInstaller.m`'s `shouldAcceptNewConnection:` only enforces `SUCodeSigningVerifier validateConnection:` before stage 1 completes. After `_performedStage1Installation = YES`, new connections to the registered Mach service `<bundleId>-spki` are accepted from any local process without team-ID or code-signing checks. As of time of publication, no known patched versions are available.
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Analysis
by VulDB Data Team • 07/21/2026
The Sparkle software update framework for macOS presents a critical security vulnerability in its autoupdate functionality that stems from inadequate code signing validation during the update process. This flaw exists in versions up to and including 2.9.1 where the `shouldAcceptNewConnection:` method in `Autoupdate/AppInstaller.m` fails to maintain consistent security checks throughout the entire installation lifecycle. The vulnerability manifests as a temporal window where the framework performs initial code signing verification through `SUCodeSigningVerifier validateConnection:` but subsequently relaxes these security measures once stage 1 of the installation process completes, creating an exploitable gap in the authorization mechanism.
The technical implementation of this vulnerability involves the framework's handling of Mach service connections during software updates. When a new update connection is established to the registered Mach service with the `-spki` identifier, the system initially validates the connection through code signing checks that verify the connecting process's team identifier and proper code signing credentials. However, after `_performedStage1Installation = YES` is set, the framework accepts all subsequent connections from any local process without performing the required team-ID or code-signing verification, effectively bypassing security controls that should remain active throughout the entire update process. This design flaw represents a clear violation of principle of least privilege and demonstrates poor access control implementation.
The operational impact of this vulnerability extends beyond simple privilege escalation to potentially enable arbitrary code execution within the context of the Sparkle framework's update process. Attackers could exploit this weakness by creating malicious local processes that connect to the registered Mach service after stage 1 completion, effectively bypassing the code signing protections that are meant to ensure only legitimate update packages are installed. This vulnerability aligns with CWE-284 (Improper Access Control) and represents a significant concern for macOS systems that rely on Sparkle for software updates, as it could allow attackers to install malicious software without proper authentication or code signing validation.
This security weakness directly relates to ATT&CK technique T1553.002 (Code Signing) and demonstrates how improper implementation of code signing verification can create persistent attack vectors. The vulnerability's temporal nature makes it particularly dangerous because it operates during a critical phase of the software update lifecycle when system integrity is most vulnerable. Organizations deploying Sparkle-based applications should be aware that this flaw could be exploited to undermine the security of their entire software distribution pipeline, as the framework's update mechanism becomes a potential backdoor for malicious actors.
The remediation approach for this vulnerability requires implementing consistent code signing validation throughout the entire installation process, ensuring that all connections to the Mach service maintain the same security requirements regardless of installation stage. This involves modifying the `shouldAcceptNewConnection:` method to continue enforcing team-ID and code-signing checks even after stage 1 completion. Additionally, implementing proper access control mechanisms for the Mach service registration and ensuring that only processes with appropriate code signing certificates can establish connections would address this vulnerability comprehensively. The lack of patched versions at publication time indicates a critical gap in the framework's security maintenance and highlights the importance of continuous security assessment for widely-used software libraries.