CVE-2022-48991

mm/khugepaged: invoke MMU notifiers in shmem/file collapse paths

HIGH

7.8

CVSS Score

Published: October 21, 2024 at 08:06 PM UTC

Updated: August 5, 2026 at 09:24 AM UTC

1 product affected across 1 vendorLinux Kernel

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Severity

HIGH7.8

Exploit prediction

EPSS 0.3%

SSVC

No known exploit

Description

In the Linux kernel, the following vulnerability has been resolved: mm/khugepaged: invoke MMU notifiers in shmem/file collapse paths Any codepath that zaps page table entries must invoke MMU notifiers to ensure that secondary MMUs (like KVM) don't keep accessing pages which aren't mapped anymore. Secondary MMUs don't hold their own references to pages that are mirrored over, so failing to notify them can lead to page use-after-free. I'm marking this as addressing an issue introduced in commit f3f0e1d2150b ("khugepaged: add support of collapse for tmpfs/shmem pages"), but most of the security impact of this only came in commit 27e1f8273113 ("khugepaged: enable collapse pmd for pte-mapped THP"), which actually omitted flushes for the removal of present PTEs, not just for the removal of empty page tables.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Linux Kernel · Linux

95%

4.10 ≤ v < 4.14.3034.15 ≤ v < 4.19.2704.20 ≤ v < 5.4.2274.8 ≤ v < 4.14.3034.8 ≤ v < 4.19.2704.8 ≤ v < 4.9.3374.8 ≤ v < 5.10.1594.8 ≤ v < 5.15.834.8 ≤ v < 5.4.2274.8 ≤ v < 6.0.134.8 ≤ v < 6.15.11 ≤ v < 5.15.835.16 ≤ v < 6.0.135.5 ≤ v < 5.10.1596.1 rc1 6.1 rc2 6.1 rc3 6.1 rc4 6.1 rc5 6.1 rc6 6.1 rc7f3f0e1d2150b2b99da2cbdfaad000089efe9bf30

Vendor states this is fixed in 1a3f8c6cd29d9078cc81b29d39d0e9ae1d6a03c3 (fixed)

Vendor states this is fixed in 275c626c131cfe141beeb6c575e31fa53d32da19 (fixed)

Vendor states this is fixed in 5450535901d89a5dcca5fbbc59a24fe89caeb465 (fixed)

Vendor states this is fixed in 5ffc2a75534d9d74d49760f983f8eb675fa63d69 (fixed)

Vendor states this is fixed in 7f445ca2e0e59c7971d0b7b853465e50844ab596 (fixed)

Vendor states this is fixed in c23105673228c349739e958fa33955ed8faddcaf (fixed)

Vendor states this is fixed in f268f6cf875f3220afc77bdd0bf1bb136eb54db9 (fixed)

Vendor states this is fixed in ff2a1a6f869650aec99e9d070b5ab625bfbc5bc3 (fixed)

Vendor states this is fixed in 4.14.303 (unaffected)

Vendor states this is fixed in 4.19.270 (unaffected)

Vendor states this is fixed in 4.8 (unaffected)

Vendor states this is fixed in 4.9.337 (unaffected)