CVE-2026-100073 ext4: fix transaction overflow during writeback
Insufficient transaction credit reservation in ext4 writeback can cause kernel crashes, leading to denial of service for local attackers.
- 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-2026-100073?
CVE-2026-100073 is a medium-severity denial of service vulnerability in Linux kernel, published on 25 Sep 2026. 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:
ext4: fix transaction overflow during writeback
Commit 95ad8ee45cdb ("ext4: correct the reserved credits for extent conversion") was correct to note that we need to reserve enough credits for all extents possibly underlying a large folio. However it was too eager to reduce the number of reserved credits. Extent conversion may not only need to touch several leaf extent blocks, it may also need to split extents - for example a single large unwritten extent may need to be split into many small written ones in case of sparse folio dirtying. This can thus result not only in extent leaf modifications but also in a need to allocate new extent tree nodes. As a result the reserved transaction credits were not sufficient in some corner cases. Use ext4_meta_trans_blocks() for correct upper bound credit estimate.
Weakness: CWE-617
Which versions are affected by CVE-2026-100073?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-100073?
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-2026-100073 being exploited?
There is no known exploitation of CVE-2026-100073 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-100073, DEBIAN-CVE-2026-100073, GHSA-4m7h-6q45-6mjf, UBUNTU-CVE-2026-100073.