CVE-2025-21667 iomap: avoid avoid truncating 64-bit offset to 32 bits
A 32-bit integer truncation in the Linux kernel's iomap subsystem can cause an infinite loop during XFS writes, leading to a denial of service.
- 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-2025-21667?
CVE-2025-21667 is a medium-severity denial of service vulnerability in Linux kernel, published on 31 Jan 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:
iomap: avoid avoid truncating 64-bit offset to 32 bits
on 32-bit kernels, iomap_write_delalloc_scan() was inadvertently using a 32-bit position due to folio_next_index() returning an unsigned long. This could lead to an infinite loop when writing to an xfs filesystem.
Weakness: CWE-835
Which versions are affected by CVE-2025-21667?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-21667?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-21667 being exploited?
There is no known exploitation of CVE-2025-21667 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-56351, AZL-56357, BELL-CVE-2025-21667, DEBIAN-CVE-2025-21667, GHSA-hf7q-8rrj-f5pv, ROOT-OS-UBUNTU-2204-CVE-2025-21667 and 1 more.