CVE-2026-46115 block: add pgmap check to biovec_phys_mergeable
Improper merging of physically contiguous block vectors from different device memory maps can lead to incorrect memory access or data corruption in the Linux kernel.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-46115?
CVE-2026-46115 is a critical vulnerability in Linux kernel, published on 28 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
block: add pgmap check to biovec_phys_mergeable
biovec_phys_mergeable() is used by the request merge, DMA mapping, and integrity merge paths to decide if two physically contiguous bvec segments can be coalesced into one. It currently has no check for whether the segments belong to different dev_pagemaps.
When zone device memory is registered in multiple chunks, each chunk gets its own dev_pagemap. A single bio can legitimately contain bvecs from different pgmaps -- iov_iter_extract_bvecs() breaks at pgmap boundaries but the outer loop in bio_iov_iter_get_pages() continues filling the same bio. If such bvecs are physically contiguous, biovec_phys_mergeable() will coalesce them, making it impossible to recover the correct pgmap for the merged segment via page_pgmap().
Add a zone_device_pages_have_same_pgmap() check to prevent merging bvec segments that span different pgmaps.
Weakness: CWE-20
Which versions are affected by CVE-2026-46115?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-46115?
Apply the vendor's patch.
Is CVE-2026-46115 being exploited?
There is no known exploitation of CVE-2026-46115 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-88812, BELL-CVE-2026-46115, DEBIAN-CVE-2026-46115, GHSA-3588-2x8w-w62r, ROOT-OS-UBUNTU-2404-CVE-2026-46115, UBUNTU-CVE-2026-46115.