CVE-2025-40200 Squashfs: reject negative file sizes in squashfs_read_inode()
A local attacker can cause a kernel warning and potential denial of service by mounting a crafted Squashfs image with negative file sizes.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-40200?
CVE-2025-40200 is a vulnerability in Linux, published on 12 Nov 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:
Squashfs: reject negative file sizes in squashfs_read_inode()
Syskaller reports a "WARNING in ovl_copy_up_file" in overlayfs.
This warning is ultimately caused because the underlying Squashfs file system returns a file with a negative file size.
This commit checks for a negative file size and returns EINVAL.
[[email protected]: only need to check 64 bit quantity]
Which versions are affected by CVE-2025-40200?
How do I fix CVE-2025-40200?
Apply the vendor's patch.
Is CVE-2025-40200 being exploited?
There is no known exploitation of CVE-2025-40200 in the wild and no public exploit code.
Sources
Also known as AZL-70073, BELL-CVE-2025-40200, DEBIAN-CVE-2025-40200, GHSA-w4gv-xmrm-6wxx, ROOT-OS-UBUNTU-2404-CVE-2025-40200, UBUNTU-CVE-2025-40200.