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Medium severity6.2NVD Advisory· Published Apr 22, 2026· Updated May 1, 2026

CVE-2026-6386

CVE-2026-6386

Description

In order to apply a particular protection key to an address range, the kernel must update the corresponding page table entries. The subroutine which handled this failed to take into account the presence of 1GB largepage mappings created using the shm_create_largepage(3) interface. In particular, it would always treat a page directory page entry as pointing to another page table page.

The bug can be abused by an unprivileged user to cause pmap_pkru_update_range() to treat userspace memory as a page table page, and thus overwrite memory to which the application would otherwise not have access.

Affected products

33
  • FreeBSD/FreeBSD33 versions
    cpe:2.3:o:freebsd:freebsd:13.5:-:*:*:*:*:*:*+ 32 more
    • cpe:2.3:o:freebsd:freebsd:13.5:-:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:13.5:beta3:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:13.5:p1:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:13.5:p10:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:13.5:p11:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:13.5:p2:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:13.5:p3:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:13.5:p4:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:13.5:p5:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:13.5:p6:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:13.5:p7:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:13.5:p8:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:13.5:p9:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:14.3:-:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:14.3:p1:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:14.3:p10:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:14.3:p2:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:14.3:p3:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:14.3:p4:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:14.3:p5:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:14.3:p6:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:14.3:p7:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:14.3:p8:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:14.3:p9:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:14.4:-:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:14.4:p1:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:14.4:rc1:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:15.0:-:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:15.0:p1:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:15.0:p2:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:15.0:p3:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:15.0:p4:*:*:*:*:*:*
    • cpe:2.3:o:freebsd:freebsd:15.0:p5:*:*:*:*:*:*

Patches

0

No patches discovered yet.

Vulnerability mechanics

AI mechanics synthesis has not run for this CVE yet.

References

1

News mentions

0

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