CVE-2025-40006: linux
Vulnerability summary
CVE-2025-40006 is a high (CVSS 7.8) vulnerability in linux. EPSS estimates a 0.20% chance of exploitation in the next 30 days, higher than 9.5% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 43 · Related 38Timeline
- 20-10-2025PublishedVulnerability first disclosed.
- 05-08-2026Last modifiedVulnerability information updated.
Description
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.
CVSS metrics
5 scores · 4 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- NVDNIST7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.20%
Chance of exploitation in the next 30 days
Percentile
10%
Versus all other CVEs
30-day change
0.00 pp
From 0.20% on 20-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeNo weakness data has been published for this record.
Affected systems
Ubuntu146 products
- linuxAll versions (No fix recorded) | < 5.15.0-170.180 | < 6.8.0-106.106 | < 6.17.0-6.6
- linux-allwinner-5.19All versions (No fix recorded)
- linux-awsAll versions (No fix recorded) | < 5.15.0-1100.107 | < 6.8.0-1050.53 | < 6.17.0-1003.3
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Debian1 product
- linux< 6.1.158-1 | < 6.12.57-1 | < 6.16.10-1
Linux1 product
- linux≥ 4aae8d1c051ea00b456da6811bc36d1f69de5445, < bc1c9ce8aeff45318332035dbef9713fb9e982d7 | ≥ 4aae8d1c051ea00b456da6811bc36d1f69de5445, < 91f548e920fbf8be3f285bfa3fa045ae017e836d | ≥ 4aae8d1c051ea00b456da6811bc36d1f69de5445, < 3e851448078f5b01f6264915df3cfef75e323a12 | ≥ 4aae8d1c051ea00b456da6811bc36d1f69de5445, < c1dc0524ab2cc3982d4e0d2bfac71a0cd4d65c39 | ≥ 4aae8d1c051ea00b456da6811bc36d1f69de5445, < c9c2a51f91aea70e89b496cac360cd795a2b3c26 | ≥ 4aae8d1c051ea00b456da6811bc36d1f69de5445, < 910d7749346c4b0acdc6e4adfdc4a9984281a206 | ≥ 4aae8d1c051ea00b456da6811bc36d1f69de5445, < 21ee79ce938127f88fe07e409c1817f477dbe7ea | ≥ 4aae8d1c051ea00b456da6811bc36d1f69de5445, < 7b7387650dcf2881fd8bb55bcf3c8bd6c9542dd7 | 4.5
3 vendors · 148 products
