CVE-2025-37863 ovl: don't allow datadir only
A local attacker can cause a kernel Oops and denial of service by configuring overlayfs with a datadir but no lowerdir.
- 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-2025-37863?
CVE-2025-37863 is a medium-severity vulnerability in Linux kernel, published on 9 May 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:
ovl: don't allow datadir only
In theory overlayfs could support upper layer directly referring to a data layer, but there's no current use case for this.
Originally, when data-only layers were introduced, this wasn't allowed, only introduced by the "datadir+" feature, but without actually handling this case, resulting in an Oops.
Fix by disallowing datadir without lowerdir.
Which versions are affected by CVE-2025-37863?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-37863?
Apply the vendor's patch.
Is CVE-2025-37863 being exploited?
There is no known exploitation of CVE-2025-37863 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2025-37863, DEBIAN-CVE-2025-37863, GHSA-h6p5-jr3p-xjfg, ROOT-OS-UBUNTU-2204-CVE-2025-37863, ROOT-OS-UBUNTU-2404-CVE-2025-37863, UBUNTU-CVE-2025-37863.