Privilege Escalation via Race Condition in Xen Grant-Copy
CVE-2026-62428 Published on July 28, 2026
grant-table: type confusion in grant-copy
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.
Vulnerability Analysis
CVE-2026-62428 is exploitable with local system access, and requires small amount of user privileges. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to be very high.
Weakness Type
What is a TOCTTOU Vulnerability?
The software checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check. This can cause the software to perform invalid actions when the resource is in an unexpected state. This weakness can be security-relevant when an attacker can influence the state of the resource between check and use. This can happen with shared resources such as files, memory, or even variables in multithreaded programs.
CVE-2026-62428 has been classified to as a TOCTTOU vulnerability or weakness.
Products Associated with CVE-2026-62428
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