CVE-2026-46115

block: add pgmap check to biovec_phys_mergeable

State: Published
Severity: 9.8 Critical
Published: May 28, 2026
Updated: Oct 19, 2026
Reserved: May 13, 2026

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.

Scores

CVSS	Score	Vector	Source
3.1	9.8 Critical	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H	Linux

Weaknesses

CWE-20 Improper Input Validation

Affected Products

Product	Versions
LinuxLinux	49580e690755d0e51ed7aa2c33225dd884fa738a to before 3d2ecbd444b01d6500671d1a582b7393943cf539Affected 49580e690755d0e51ed7aa2c33225dd884fa738a to before a7f3aa8c9df3905fe820ae36b67ba56b81587574Affected 49580e690755d0e51ed7aa2c33225dd884fa738a to before f17d521075325b8afc42d1baa1c28a5e9aca111fAffected 49580e690755d0e51ed7aa2c33225dd884fa738a to before f632dab4b841554cd6416058c61886d7db176581Affected 49580e690755d0e51ed7aa2c33225dd884fa738a to before 13920e4b7b784b40cf4519ff1f0f3e513476a499Affected
LinuxLinux	6.2Affected before 6.2Not affected 6.6.140 through 6.6.Not affected 6.12.88 through 6.12.Not affected 6.18.30 through 6.18.Not affected 7.0.7 through 7.0.Not affected 7.1 and laterNot affected

Product

Versions

LinuxLinux

49580e690755d0e51ed7aa2c33225dd884fa738a to before 3d2ecbd444b01d6500671d1a582b7393943cf539Affected
49580e690755d0e51ed7aa2c33225dd884fa738a to before a7f3aa8c9df3905fe820ae36b67ba56b81587574Affected
49580e690755d0e51ed7aa2c33225dd884fa738a to before f17d521075325b8afc42d1baa1c28a5e9aca111fAffected
49580e690755d0e51ed7aa2c33225dd884fa738a to before f632dab4b841554cd6416058c61886d7db176581Affected
49580e690755d0e51ed7aa2c33225dd884fa738a to before 13920e4b7b784b40cf4519ff1f0f3e513476a499Affected

LinuxLinux

6.2Affected
before 6.2Not affected
6.6.140 through 6.6.*Not affected
6.12.88 through 6.12.*Not affected
6.18.30 through 6.18.*Not affected
7.0.7 through 7.0.*Not affected
7.1 and laterNot affected

References

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