Linux Kernel up to 7.2-rc5 huge_memory mm/huge_memory.c __folio_split use after free

CVSS Meta Temp Score
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CTI Interest Score
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9.5$5k-$25k0.00

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.6.150/6.12.102/6.18.43/7.1.7/7.2-rc5. It has been classified as very critical. This impacts the function __folio_split of the file mm/huge_memory.c of the component huge_memory. The manipulation leads to use after free. This vulnerability is listed as CVE-2026-74482. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability, which was classified as very critical, has been found in Linux Kernel up to 6.6.150/6.12.102/6.18.43/7.1.7/7.2-rc5. This issue affects the function __folio_split of the file mm/huge_memory.c of the component huge_memory. The manipulation with an unknown input leads to a use after free vulnerability. Using CWE to declare the problem leads to CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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: drop i_mmap_rwsem right after remap_page(), before the loop that unlocks and frees the after-split folios, and clear @mapping so the exit path does not unlock it again. shmem_uncharge() and remap_page() already run before that point, so after this nothing past the unlock loop touches the inode or the mapping. This is now a rule the split depends on, alongside keeping @folio frozen until the page cache is updated: no inode or mapping dereference once the after-split folios start being unlocked.

The advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2026-74482 since 08/15/2026. The exploitation is known to be easy. The attack may be initiated remotely. Technical details are known, but no exploit is available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 08/15/2026).

Upgrading to version 6.6.151, 6.12.103, 6.18.44, 7.1.8 or 7.2-rc6 eliminates this vulnerability. Applying the patch be106f7855f03d3128ed0ce70ba74b484a90b473/e3dd774dbfd0b5bc2dbd0995221751b1234f8205/10065fb891651d9541e7a5a2db84c1e656ece4f9/d640efe94d86d3be893d4c19220362546a637e90/e923bd21058ea02fd0dcd3549d151d143fd036e5 is able to eliminate this problem.

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Productinfo

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Vendor

Name

Version

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Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 9.9
VulDB Meta Temp Score: 9.5

VulDB Base Score: 9.9
VulDB Temp Score: 9.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.6.151/6.12.103/6.18.44/7.1.8/7.2-rc6
Patch: be106f7855f03d3128ed0ce70ba74b484a90b473/e3dd774dbfd0b5bc2dbd0995221751b1234f8205/10065fb891651d9541e7a5a2db84c1e656ece4f9/d640efe94d86d3be893d4c19220362546a637e90/e923bd21058ea02fd0dcd3549d151d143fd036e5

Timelineinfo

08/15/2026 Advisory disclosed
08/15/2026 +0 days CVE reserved
08/15/2026 +0 days VulDB entry created
08/15/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-74482 (🔒)
GCVE (CVE): GCVE-0-2026-74482
GCVE (VulDB): GCVE-100-390773

Entryinfo

Created: 08/15/2026 14:56
Changes: 08/15/2026 14:56 (60)
Complete: 🔍
Cache ID: 216::103

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