CVE-2026-90161 erofs: fix interlaced ztailpacking pclusters
A crafted EROFS filesystem image can trigger an out-of-bounds read, leaking kernel memory to userspace via the page cache.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-90161?
CVE-2026-90161 is a high-severity vulnerability in Linux, published on 17 Sep 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
In the Linux kernel, the following vulnerability has been resolved:
erofs: fix interlaced ztailpacking pclusters
On-disk sizes of interlaced pclusters should be block-aligned, and ztailpacking interlaced pclusters should be invalid at all.
Currently, mkfs.erofs won't generate any interlaced pcluster with ztailpacking enabled, so this doesn't affect any existing valid filesystems.
However, crafted images can contain invalid interlaced ztailpacking pclusters, resulting in an out-of-bounds read from a kmap'd page and copying irrelevant kernel memory into userspace-visible page cache.
Which versions are affected by CVE-2026-90161?
How do I fix CVE-2026-90161?
Apply the vendor's patch.
Is CVE-2026-90161 being exploited?
There is no known exploitation of CVE-2026-90161 in the wild and no public exploit code.
Sources
Also known as AZL-103047, BELL-CVE-2026-90161, DEBIAN-CVE-2026-90161, GHSA-75m6-v57w-mhq4, UBUNTU-CVE-2026-90161.