CVE-2024-43828 ext4: fix infinite loop when replaying fast_commit
An attacker can cause a denial of service via an infinite loop in the Linux kernel ext4 filesystem during fast_commit replay.
- 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-2024-43828?
CVE-2024-43828 is a medium-severity denial of service vulnerability in Linux kernel, published on 17 Aug 2024. 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 infinite loop when replaying fast_commit
When doing fast_commit replay an infinite loop may occur due to an uninitialized extent_status struct. ext4_ext_determine_insert_hole() does not detect the replay and calls ext4_es_find_extent_range(), which will return immediately without initializing the 'es' variable.
Because 'es' contains garbage, an integer overflow may happen causing an infinite loop in this function, easily reproducible using fstest generic/039.
This commit fixes this issue by unconditionally initializing the structure in function ext4_es_find_extent_range().
Thanks to Zhang Yi, for figuring out the real problem!
Weakness: CWE-835
Which versions are affected by CVE-2024-43828?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2024-43828?
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-2024-43828 being exploited?
There is no known exploitation of CVE-2024-43828 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-47940, AZL-48045, BELL-CVE-2024-43828, DEBIAN-CVE-2024-43828, GHSA-hx96-9f4r-rwcp, UBUNTU-CVE-2024-43828.