CVE-2022-48991
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…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.25%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public 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.
- CVSS 3.1
- 7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.25% probability · 17th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-416
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/1a3f8c6cd29d9078cc81b29d39d0e9ae1d6a03c3Patch
- https://git.kernel.org/stable/c/275c626c131cfe141beeb6c575e31fa53d32da19Patch
- https://git.kernel.org/stable/c/5450535901d89a5dcca5fbbc59a24fe89caeb465Patch
- https://git.kernel.org/stable/c/5ffc2a75534d9d74d49760f983f8eb675fa63d69Patch
- https://git.kernel.org/stable/c/7f445ca2e0e59c7971d0b7b853465e50844ab596Patch
- https://git.kernel.org/stable/c/c23105673228c349739e958fa33955ed8faddcafPatch
- https://git.kernel.org/stable/c/f268f6cf875f3220afc77bdd0bf1bb136eb54db9Patch
- https://git.kernel.org/stable/c/ff2a1a6f869650aec99e9d070b5ab625bfbc5bc3Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.