CVE-2026-62428 in Xen
Summary
by MITRE • 07/28/2026
When grant-copy operations are processed, the respective grant may or may not already be in use by another operation (a mapping or another copy). For all copy operations the referenced guest frame is looked up. When another operation is already active for the grant (the grant is "pinned"), what is being supplied back to actually carry out permission checks and copy operation may not be consistent: The permission check may be carried out on a page different from the one involved in the copy.
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Analysis
by VulDB Data Team • 07/28/2026
This vulnerability describes a critical race condition and inconsistent state management issue within virtualization grant copy operations that can lead to privilege escalation and unauthorized data access. The flaw occurs when multiple concurrent operations attempt to process grant-copy operations on the same grant identifier, creating a scenario where the system's internal state becomes inconsistent between permission validation and actual execution phases.
The technical implementation involves a mapping system where guest frames are looked up during copy operations, but when a grant is already "pinned" by another active operation, the system fails to maintain consistent references between permission checks and actual data transfer mechanisms. This inconsistency creates a potential attack surface where malicious actors could exploit the temporal gap between validation and execution to bypass security controls.
From a cybersecurity perspective, this vulnerability aligns with CWE-362, which addresses race conditions in concurrent systems, and represents a classic example of how improper synchronization can lead to privilege escalation. The ATT&CK framework categorizes this under privilege escalation techniques where adversaries manipulate system state to gain elevated permissions.
The operational impact of this vulnerability is severe as it allows for potential unauthorized data access and modification across virtualized environments. An attacker could exploit this inconsistency to perform operations that should be restricted, potentially gaining access to sensitive information or system resources that would normally be protected by proper permission controls.
Mitigation strategies should focus on implementing proper synchronization mechanisms around grant operations, ensuring consistent references between permission checks and execution phases. System designers should employ atomic operations or mutex locks to prevent concurrent access to the same grant during critical operation phases. Additionally, implementing comprehensive logging and monitoring of grant operations can help detect anomalous behavior patterns that might indicate exploitation attempts.
The vulnerability demonstrates the importance of maintaining consistency in virtualization systems where multiple operations may reference shared resources, highlighting the need for robust state management and proper concurrency control mechanisms. Organizations should also consider implementing regular security assessments of virtualization components to identify similar race condition vulnerabilities that could compromise system integrity and data confidentiality.