mm/huge_memory: unlock i_mmap_rwsem before releasing after-split folios
In the Linux kernel, the following vulnerability has been resolved: mm/huge_memory: unlock i_mmap_rwsem before releasing after-split folios __folio_split() keeps dereferencing the mapping after the split: shmem_uncharge(mapping->host) and remap_page() while the folios are still frozen/locked, and i_mmap_unlock_read(mapping) at the very end, after the after-split folios have been unlocked and freed. Nothing holds an inode reference across that. The split relies on @folio -- which the beyond-EOF drop loop never removes, as it starts at folio_next(folio) -- staying locked and in the page cache to hold off eviction. But the unlock loop unlocks @folio before i_mmap_unlock_read() runs. If the caller's @lock_at is a tail beyond EOF, as memory_failure() passes when splitting a poisoned tail of a shmem THP that reaches past i_size during truncation, it too is gone from the page cache; so once @folio is unlocked no locked, in-cache folio pins the inode, and a concurrent final iput() can evict and RCU-free it before i_mmap_unlock_read() touches i_mmap_rwsem: BUG: KASAN: slab-use-after-free in __up_read+0x634/0x790 i_mmap_unlock_read include/linux/fs.h:537 [inline] __folio_split+0x732/0x1640 mm/huge_memory.c:4100 try_to_split_thp_page+0xab/0x390 mm/memory-failure.c:1675 memory_failure+0x1394/0x26e0 mm/memory-failure.c:2470 Freed by task 4601: shmem_free_in_core_inode+0x54/0xb0 mm/shmem.c:5177 evict+0x57f/0xac0 fs/inode.c:870 Do every mapping dereference while @folio still pins the inode:
CVE-2026-74482
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-74482
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "baa355fd331424526e742d41d9b90d5f9d10f716",
"lessThan": "bc2f5eabaaf60ec18da70b619a8fba1bfb7dea3a",
"versionType": "git"
},
{
"status": "affected",
"version": "baa355fd331424526e742d41d9b90d5f9d10f716",
"lessThan": "f87c08060818ebb19bafed37c38244538da25097",
"versionType": "git"
},
{
"status": "affected",
"version": "baa355fd331424526e742d41d9b90d5f9d10f716",
"lessThan": "6f5c272d71845a669e4c8ee5c72b376e29a0e6e5",
"versionType": "git"
},
{
"status": "affected",
"version": "baa355fd331424526e742d41d9b90d5f9d10f716",
"lessThan": "be106f7855f03d3128ed0ce70ba74b484a90b473",
"versionType": "git"
},
{
"status": "affected",
"version": "baa355fd331424526e742d41d9b90d5f9d10f716",
"lessThan": "e3dd774dbfd0b5bc2dbd0995221751b1234f8205",
"versionType": "git"
},
{
"status": "affected",
"version": "baa355fd331424526e742d41d9b90d5f9d10f716",
"lessThan": "10065fb891651d9541e7a5a2db84c1e656ece4f9",
"versionType": "git"
},
{
"status": "affected",
"version": "baa355fd331424526e742d41d9b90d5f9d10f716",
"lessThan": "d640efe94d86d3be893d4c19220362546a637e90",
"versionType": "git"
},
{
"status": "affected",
"version": "baa355fd331424526e742d41d9b90d5f9d10f716",
"lessThan": "e923bd21058ea02fd0dcd3549d151d143fd036e5",
"versionType": "git"
}
],
"programFiles": [
"mm/huge_memory.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4.8"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "4.8",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.265",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.216",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.183",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.151",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.103",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.44",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.8",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"mm/huge_memory.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-74482
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #33174 · Revision 1
- Added to Heist Feed
- Publisher date