mm/khugepaged: invoke MMU notifiers in shmem/file collapse paths
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 4 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-416 and the CVSS impact.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 4.8 and later | 4.9.337, 4.14.303, 4.19.270, 5.4.227, 5.10.159, 5.15.83, 6.0.13, 6.1 | Patch available | CNA |
- Linux VendorLinux Affected 4.8 and later Fixed in 4.9.337, 4.14.303, 4.19.270, 5.4.227, 5.10.159, 5.15.83, 6.0.13, 6.1 Patch available CNA
CPE configurations NVD · 8
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 4.8 to before 4.9.337; 4.10 to before 4.14.303; 4.15 to before 4.19.270; 4.20 to before 5.4.227; 5.5 to before 5.10.159; 5.11 to before 5.15.83; 5.16 to before 6.0.13 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.1:rc1:*:*:*:*:*:* | 6.1 rc1 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.1:rc2:*:*:*:*:*:* | 6.1 rc2 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.1:rc3:*:*:*:*:*:* | 6.1 rc3 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.1:rc4:*:*:*:*:*:* | 6.1 rc4 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.1:rc5:*:*:*:*:*:* | 6.1 rc5 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.1:rc6:*:*:*:*:*:* | 6.1 rc6 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.1:rc7:*:*:*:*:*:* | 6.1 rc7 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 4.8 to before 4.9.337; 4.10 to before 4.14.303; 4.15 to before 4.19.270; 4.20 to before 5.4.227; 5.5 to before 5.10.159; 5.11 to before 5.15.83; 5.16 to before 6.0.13 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.1:rc1:*:*:*:*:*:* Versions 6.1 rc1 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.1:rc2:*:*:*:*:*:* Versions 6.1 rc2 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.1:rc3:*:*:*:*:*:* Versions 6.1 rc3 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.1:rc4:*:*:*:*:*:* Versions 6.1 rc4 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.1:rc5:*:*:*:*:*:* Versions 6.1 rc5 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.1:rc6:*:*:*:*:*:* Versions 6.1 rc6 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.1:rc7:*:*:*:*:*:* Versions 6.1 rc7 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 4.9.337, 4.14.303, 4.19.270, 5.4.227, 5.10.159, 5.15.83, 6.0.13, 6.1
Red Hat 1 advisory
- RHSA-2023:6583 Released 2023-11-07 · Red Hat rating Importantkernel security, bug fix, and enhancement update
- Red Hat CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-362.8.1.el9_3, libperf-5.14.0-362.8.1.el9_3
- Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-362.8.1.el9_3, kernel-64k-debug-devel-matched-5.14.0-362.8.1.el9_3, kernel-64k-devel-5.14.0-362.8.1.el9_3 +11
- Red Hat Enterprise Linux BaseOS (v. 9) bpftool-7.2.0-362.8.1.el9_3, kernel-5.14.0-362.8.1.el9_3, kernel-64k-5.14.0-362.8.1.el9_3 +29
- Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-362.8.1.el9_3, kernel-rt-core-5.14.0-362.8.1.el9_3, kernel-rt-debug-5.14.0-362.8.1.el9_3 +9
- Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-362.8.1.el9_3, kernel-rt-core-5.14.0-362.8.1.el9_3, kernel-rt-debug-5.14.0-362.8.1.el9_3 +11
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 8 | Affected | No fix planned: Will not fix |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Timeline
- 2026-10-02 Threatist record created from CVE-2022-48991
- 2026-10-03 Alias added: GHSA-8xxh-66cx-j9cj
References
Patch 8
- https://git.kernel.org/stable/c/275c626c131cfe141beeb6c575e31fa53d32da19
- https://git.kernel.org/stable/c/c23105673228c349739e958fa33955ed8faddcaf
- https://git.kernel.org/stable/c/ff2a1a6f869650aec99e9d070b5ab625bfbc5bc3
- https://git.kernel.org/stable/c/5ffc2a75534d9d74d49760f983f8eb675fa63d69
- https://git.kernel.org/stable/c/7f445ca2e0e59c7971d0b7b853465e50844ab596
- https://git.kernel.org/stable/c/1a3f8c6cd29d9078cc81b29d39d0e9ae1d6a03c3
- https://git.kernel.org/stable/c/5450535901d89a5dcca5fbbc59a24fe89caeb465
- https://git.kernel.org/stable/c/f268f6cf875f3220afc77bdd0bf1bb136eb54db9
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Sources
- CVE-2022-48991 · CVE Program
- CVE-2022-48991 · NVD
- FIRST EPSS
- GHSA-8xxh-66cx-j9cj · GitHub Advisory Database · CC BY 4.0
- CVE-2022-48991 · Red Hat security data · CC BY 4.0
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