CVE-2022-49989: xen/privcmd: fix error exit of privcmd_ioctl_dm_op()

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-06-18 · updated 2026-06-17
Weakness: CWE-476

Description

In the Linux kernel, the following vulnerability has been resolved: xen/privcmd: fix error exit of privcmd_ioctl_dm_op() The error exit of privcmd_ioctl_dm_op() is calling unlock_pages() potentially with pages being NULL, leading to a NULL dereference. Additionally lock_pages() doesn't check for pin_user_pages_fast() having been completely successful, resulting in potentially not locking all pages into memory. This could result in sporadic failures when using the related memory in user mode. Fix all of that by calling unlock_pages() always with the real number of pinned pages, which will be zero in case pages being NULL, and by checking the number of pages pinned by pin_user_pages_fast() matching the expected number of pages.

Affected products

Linux kernel: from 4.11 before 5.10.140; from 5.11 before 5.15.64; from 5.16 before 5.19.6; 6.0-rc1, 6.0-rc2 — fixed in 5.10.140, 5.15.64, 5.19.6

How to fix

Upgrade to a fixed version: Linux kernel 5.10.140, 5.15.64, 5.19.6. Check the vendor advisory for mitigations.

References

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