CVE-2025-38688 iommufd: Prevent ALIGN() overflow
An integer overflow in the Linux kernel iommufd subsystem allows userspace to create overlapping memory mappings, potentially leading to data corruption or unauthorized access.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-38688?
CVE-2025-38688 is a high-severity vulnerability in Linux kernel, published on 4 Sep 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
iommufd: Prevent ALIGN() overflow
When allocating IOVA the candidate range gets aligned to the target alignment. If the range is close to ULONG_MAX then the ALIGN() can wrap resulting in a corrupted iova.
Open code the ALIGN() using get_add_overflow() to prevent this. This simplifies the checks as we don't need to check for length earlier either.
Consolidate the two copies of this code under a single helper.
This bug would allow userspace to create a mapping that overlaps with some other mapping or a reserved range.
Which versions are affected by CVE-2025-38688?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-38688?
Apply the vendor's patch.
Is CVE-2025-38688 being exploited?
There is no known exploitation of CVE-2025-38688 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2025-38688, DEBIAN-CVE-2025-38688, GHSA-4fjc-772g-jpj6, ROOT-OS-UBUNTU-2404-CVE-2025-38688, UBUNTU-CVE-2025-38688.