CVE-2026-6386 (GCVE-0-2026-6386)
Vulnerability from cvelistv5 – Published: 2026-04-22 02:33 – Updated: 2026-04-22 14:32
VLAI
EPSS
VEX
Title
Missing large page handling in pmap_pkru_update_range()
Summary
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.
Severity
6.2 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-04-22 14:26 UTC
CWE
Assigner
freebsd
CNA
References
1 reference
| URL | Tags |
|---|---|
| https://security.freebsd.org/advisories/FreeBSD-S… | vendor-advisory |
Impacted products
Date Public
2026-04-21 18:00
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