CVE-2026-72138: xen/gntdev: fix error handling in ioctl
In the Linux kernel, the following vulnerability has been resolved:
xen/gntdev: fix error handling in ioctl
When gntdevioctlmapgrantref() fails to copy the operation result back to userspace after successfully adding the mapping to the list, the error path returns -EFAULT without releasing the reference acquired by gntdevallocmap(). The mapping remains in priv->maps with a refcount of 1, causing a memory leak and a dangling list entry.
Additionally, gntdevaddmap() may modify map->index to avoid overlap with existing mappings. Therefore, the index returned to userspace must be obtained after gntdevaddmap() completes.
Fix this by holding the mutex across gntdevaddmap(), retrieving the correct index, and copytouser(). If copytouser() fails, remove the mapping from the list and release the reference while still holding the lock.
Fix these issues by properly handling all error cases.
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-72138?
CVE-2026-72138 has a risk rating of 27, indicating a potentially high impact.
How do I fix CVE-2026-72138?
Fixing CVE-2026-72138 involves updating the Linux kernel to a version where the issue has been addressed.
What are the potential consequences of CVE-2026-72138?
CVE-2026-72138 may lead to improper error handling, which can result in unexpected behaviors in applications using the Linux kernel.
Who is affected by CVE-2026-72138?
CVE-2026-72138 affects users running vulnerable versions of the Linux kernel that implement gntdev functionality.
Is CVE-2026-72138 related to virtualization?
Yes, CVE-2026-72138 pertains to the gntdev driver in the Linux kernel, which is used in virtualization contexts for memory management.