Incorrect calculation in Linux kernel - CVE-2026-98226

Vulnerability details

The vulnerability allows a local user to corrupt swap accounting and availability lists and cause loss of swapped-out pages.

The vulnerability exists due to an incorrect flag-bit calculation in mm/swapfile.c when tracking swap usage with a counter that also stores the off-list flag. A local user can trigger swap usage updates with bit 30 set in the actual usage count to corrupt swap accounting and availability lists and cause loss of swapped-out pages.

On systems with 4 KiB pages, the flag overlaps the usage count at 4 TiB of swap usage. Page loss requires swapoff to run when the raw usage count is exactly 2^30 pages; availability-list corruption can occur during normal swap use without swapoff.

Affected software

How to mitigate CVE-2026-98226

External References

• https://git.kernel.org/stable/c/0a41a46859df0d2bd7ed127197aac7c7389c00ed
• https://git.kernel.org/stable/c/12e9ac7bc5b254048f886bf421e3a15491106c1f
• https://git.kernel.org/stable/c/7c0d0d6de46076b43a2acaf1026b6648f8434c39

Related Security Bulletins

• Incorrect calculation in Linux kernel mm
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more