mm/rmap: fix potential out-of-bounds page table access during batched unmap
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA.
Summary
In the Linux kernel, the following vulnerability has been resolved: mm/rmap: fix potential out-of-bounds page table access during batched unmap As pointed out by David[1], the batched unmap logic in try_to_unmap_one() may read past the end of a PTE table when a large folio's PTE mappings are not fully contained within a single page table. While this scenario might be rare, an issue triggerable from userspace must be fixed regardless of its likelihood. This patch fixes the out-of-bounds access by refactoring the logic into a new helper, folio_unmap_pte_batch(). The new helper correctly calculates the safe batch size by capping the scan at both the VMA and PMD boundaries. To simplify the code, it also supports partial batching (i.e., any number of pages from 1 up to the calculated safe maximum), as there is no strong reason to special-case for fully mapped folios.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 6.15 and later | 6.15.7, 6.16 | Patch available | CNA |
- Linux VendorLinux Affected 6.15 and later Fixed in 6.15.7, 6.16 Patch available CNA
CPE configurations NVD · 6
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 6.15 to before 6.15.7 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.16:rc1:*:*:*:*:*:* | 6.16 rc1 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.16:rc2:*:*:*:*:*:* | 6.16 rc2 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.16:rc3:*:*:*:*:*:* | 6.16 rc3 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.16:rc4:*:*:*:*:*:* | 6.16 rc4 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.16:rc5:*:*:*:*:*:* | 6.16 rc5 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 6.15 to before 6.15.7 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.16:rc1:*:*:*:*:*:* Versions 6.16 rc1 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.16:rc2:*:*:*:*:*:* Versions 6.16 rc2 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.16:rc3:*:*:*:*:*:* Versions 6.16 rc3 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.16:rc4:*:*:*:*:*:* Versions 6.16 rc4 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.16:rc5:*:*:*:*:*:* Versions 6.16 rc5 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.15.7, 6.16
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
Not affected: 5 products
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2025-38447
- 2026-10-03 Alias added: GHSA-crvf-pv9v-3xvj
- 2026-11-07 Affected versions changed · Red Hat
References
More Linux Kernel vulnerabilities
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- TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
- TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
- TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
- TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
Sources
- CVE-2025-38447 · CVE Program
- CVE-2025-38447 · NVD
- FIRST EPSS
- GHSA-crvf-pv9v-3xvj · GitHub Advisory Database · CC BY 4.0
- CVE-2025-38447 · Red Hat security data · CC BY 4.0
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