CVE-2026-53015 erofs: unify lcn as u64 for 32-bit platforms
An integer overflow in the EROFS filesystem on 32-bit platforms causes data truncation, potentially leading to data corruption 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-2026-53015?
CVE-2026-53015 is a medium-severity vulnerability in Linux kernel, published on 24 Jun 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:
erofs: unify lcn as u64 for 32-bit platforms
As sashiko reported [1], `lcn` was typed as `unsigned long` (or `unsigned int` sometimes), which is only 32 bits wide on 32-bit platforms, which causes `(lcn << lclusterbits)` to be truncated at 4 GiB.
In order to consolidate the logic, just use `u64` consistently around the codebase.
[1] https://sashiko.dev/r/20260420034612.1899973-1-hsiangkao%40linux.alibaba.com
Which versions are affected by CVE-2026-53015?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-53015?
Apply the vendor's patch.
Is CVE-2026-53015 being exploited?
There is no known exploitation of CVE-2026-53015 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-90342, BELL-CVE-2026-53015, DEBIAN-CVE-2026-53015, GHSA-v64f-8vqx-f88g, ROOT-OS-DEBIAN-11-CVE-2026-53015, ROOT-OS-DEBIAN-12-CVE-2026-53015 and 3 more.