Incorrect calculation in Linux kernel - CVE-2026-80893
Published: September 5, 2026
Vulnerability details
The vulnerability allows a local user to corrupt swap entry data.
The vulnerability exists due to improper handling of userfaultfd write-protection bits in copy_hugetlb_page_range() in mm/hugetlb.c when forking a process while a hugetlb migration entry is in flight or a hugetlb page is poisoned. A local user can fork a process under these conditions to corrupt swap entry data.
Userfaultfd does not need to be involved.
Affected software
How to mitigate CVE-2026-80893
External References
- https://git.kernel.org/stable/c/2b9a07002c2f296aa6a9c591213933d3492e3089
- https://git.kernel.org/stable/c/2fa11c60c9c06bafc19cf4d9efdaa36a38079e87
- https://git.kernel.org/stable/c/69cb5825d9988c7944bc9f1dc08cb233655405a7
- https://git.kernel.org/stable/c/83abe2fd5b3aeb3123b5408a5a91709c5538fb23
- https://git.kernel.org/stable/c/8b0de7005b148738d79d6c45594d566489948a68
- https://git.kernel.org/stable/c/f1b1311c0352873137768bac5a126e491271a747