CVE-2026-86905 in iOS
Summary
by MITRE • 09/15/2026
This issue was addressed by removing the vulnerable code. This issue is fixed in iOS 27 and iPadOS 27, macOS Golden Gate 27, visionOS 27. An app may be able to delete credentials stored in Keychain.
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Analysis
by VulDB Data Team • 09/15/2026
The vulnerability described involves a critical flaw within Apple's operating system ecosystem, specifically affecting iOS, iPadOS, macOS, and visionOS versions prior to the release of version twenty-seven across all platforms. The core technical issue stems from an improper access control mechanism or logic error that allows applications to interact with the Keychain storage subsystem in ways that were not intended by the security model. Typically, the Keychain is designed as a secure container for sensitive user data such as passwords, cryptographic keys, and certificates, where each application operates within its own isolated keychain access group. However, this flaw bypasses those isolation boundaries or permission checks, granting an app the ability to delete credentials stored in the Keychain that belong to other applications or system services. This represents a significant deviation from the principle of least privilege and data integrity expected in modern mobile and desktop operating systems.
From a technical perspective, this vulnerability aligns with CWE-250, which describes vulnerabilities where an application performs operations without sufficient privileges, leading to security bypasses. More specifically, it relates to CWE-732, concerning incorrect permission assignment for critical resources, as the app is granted write or delete permissions on data it should only have read access to, or no access at all depending on the context of deletion. The ability to arbitrarily remove credentials undermines the integrity and availability of authentication mechanisms across the device. If an attacker can exploit this flaw through a malicious application installed on the user's device, they could systematically erase login tokens, saved passwords, or API keys stored by other legitimate applications. This action does not necessarily expose the plaintext values but effectively denies access to those services for the user and potentially disrupts automated processes that rely on persistent authentication states.
The operational impact of this vulnerability is severe in terms of availability and trust within the device's security posture. By deleting credentials, an attacker can cause denial-of-service conditions for specific applications or services without needing to exfiltrate data. This could lock users out of their accounts if recovery mechanisms are not robustly implemented by the affected apps. Furthermore, it erodes user confidence in the platform's ability to protect sensitive information. In enterprise environments where single sign-on and managed device configurations rely on stable credential storage, such instability can lead to significant productivity losses and increased support overhead. The attack vector typically requires local execution with a malicious app installed, which may be facilitated through social engineering or supply chain compromises if the attacker gains access to an application distribution channel.
This behavior is also relevant to MITRE ATT&CK techniques related to Defense Evasion and Impact. Specifically, it mirrors aspects of T1562, Impair Defenses, where adversaries disable security tools or mechanisms to avoid detection or maintain persistence by disrupting authentication flows. It can also be viewed through the lens of T1489, Service Stop, if the deletion of credentials causes dependent services to halt operation due to lack of valid authentication tokens. The removal of these critical resources effectively degrades the defensive posture of the endpoint, making it more susceptible to further attacks or forcing users into insecure recovery procedures that might expose additional data.
Mitigation for this vulnerability is primarily achieved through software updates provided by Apple. Users and administrators must ensure that all devices are updated to iOS twenty-seven, iPadOS twenty-seven, macOS Golden Gate twenty-seven, or visionOS twenty-seven, as these versions contain the necessary code removals and logic fixes to prevent unauthorized deletion of Keychain items. For organizations managing fleets of devices, enforcing automatic updates via Mobile Device Management solutions is critical to ensure rapid patch deployment. Additionally, developers should review their applications for any reliance on deprecated APIs that might have contributed to this issue in older builds and adhere strictly to Apple's security guidelines regarding keychain access groups and entitlements. Regular auditing of application permissions and monitoring for anomalous behavior related to credential stores can also help detect potential exploitation attempts before significant damage occurs, although the primary defense remains timely patching of the underlying operating system components.