CVE-2025-39800 btrfs: abort transaction on unexpected eb generation at btrfs_copy_root()
A flaw in the Linux kernel's btrfs filesystem allows persisting invalid metadata, potentially leading to system instability or 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-2025-39800?
CVE-2025-39800 is a high-severity denial of service vulnerability in Debian Debian Linux, published on 15 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:
btrfs: abort transaction on unexpected eb generation at btrfs_copy_root()
If we find an unexpected generation for the extent buffer we are cloning at btrfs_copy_root(), we just WARN_ON() and don't error out and abort the transaction, meaning we allow to persist metadata with an unexpected generation. Instead of warning only, abort the transaction and return -EUCLEAN.
Which versions are affected by CVE-2025-39800?
It affects 2 products.
Products include Debian Debian Linux, Linux kernel.
How do I fix CVE-2025-39800?
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-2025-39800 being exploited?
There is no known exploitation of CVE-2025-39800 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as BELL-CVE-2025-39800, DEBIAN-CVE-2025-39800, GHSA-q638-mxxh-qchw, ROOT-OS-DEBIAN-11-CVE-2025-39800, ROOT-OS-UBUNTU-2204-CVE-2025-39800, ROOT-OS-UBUNTU-2404-CVE-2025-39800 and 1 more.