mm/hugetlb: fix folio is still mapped when deleted
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 7 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: mm/hugetlb: fix folio is still mapped when deleted Migration may be raced with fallocating hole. remove_inode_single_folio will unmap the folio if the folio is still mapped. However, it's called without folio lock. If the folio is migrated and the mapped pte has been converted to migration entry, folio_mapped() returns false, and won't unmap it. Due to extra refcount held by remove_inode_single_folio, migration fails, restores migration entry to normal pte, and the folio is mapped again. As a result, we triggered BUG in filemap_unaccount_folio. The log is as follows: BUG: Bad page cache in process hugetlb pfn:156c00 page: refcount:515 mapcount:0 mapping:0000000099fef6e1 index:0x0 pfn:0x156c00 head: order:9 mapcount:1 entire_mapcount:1 nr_pages_mapped:0 pincount:0 aops:hugetlbfs_aops ino:dcc dentry name(?):"my_hugepage_file" flags: 0x17ffffc00000c1(locked|waiters|head|node=0|zone=2|lastcpupid=0x1fffff) page_type: f4(hugetlb) page dumped because: still mapped when deleted CPU: 1 UID: 0 PID: 395 Comm: hugetlb Not tainted 6.17.0-rc5-00044-g7aac71907bde-dirty #484 NONE Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015 Call Trace: <TASK> dump_stack_lvl+0x4f/0x70 filemap_unaccount_folio+0xc4/0x1c0 __filemap_remove_folio+0x38/0x1c0 filemap_remove_folio+0x41/0xd0 remove_inode_hugepages+0x142/0x250 hugetlbfs_fallocate+0x471/0x5a0 vfs_fallocate+0x149/0x380 Hold folio lock before checking if the folio is mapped to avold race with migration.
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 | 4.5 and later | 5.4.300, 5.10.245, 5.15.194, 6.1.155, 6.6.109, 6.12.50, 6.16.10, 6.17 | Patch available | CNA |
- Linux VendorLinux Affected 4.5 and later Fixed in 5.4.300, 5.10.245, 5.15.194, 6.1.155, 6.6.109, 6.12.50, 6.16.10, 6.17 Patch available CNA
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.4.300, 5.10.245, 5.15.194, 6.1.155, 6.6.109, 6.12.50, 6.16.10, 6.17
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Timeline
- 2026-10-02 Threatist record created from CVE-2025-40006
- 2026-10-03 Alias added: GHSA-3f8h-q5gp-rc64
- 2026-11-03 Affected versions changed · Red Hat
References
Other 8
- https://git.kernel.org/stable/c/bc1c9ce8aeff45318332035dbef9713fb9e982d7
- https://git.kernel.org/stable/c/91f548e920fbf8be3f285bfa3fa045ae017e836d
- https://git.kernel.org/stable/c/3e851448078f5b01f6264915df3cfef75e323a12
- https://git.kernel.org/stable/c/c1dc0524ab2cc3982d4e0d2bfac71a0cd4d65c39
- https://git.kernel.org/stable/c/c9c2a51f91aea70e89b496cac360cd795a2b3c26
- https://git.kernel.org/stable/c/910d7749346c4b0acdc6e4adfdc4a9984281a206
- https://git.kernel.org/stable/c/21ee79ce938127f88fe07e409c1817f477dbe7ea
- https://git.kernel.org/stable/c/7b7387650dcf2881fd8bb55bcf3c8bd6c9542dd7
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Sources
- CVE-2025-40006 · CVE Program
- CVE-2025-40006 · NVD
- FIRST EPSS
- GHSA-3f8h-q5gp-rc64 · GitHub Advisory Database · CC BY 4.0
- CVE-2025-40006 · Red Hat security data · CC BY 4.0
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