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CVE-2026-74482— mm/huge_memory: unlock i_mmap_rwsem before releasing after-split folios

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会开源的一个操作系统内核。 Linux kernel存在安全漏洞，该漏洞源于mm/huge_memory.c中的__folio_split()函数在拆分后释放folio时未正确持有inode引用，仍对mapping进行解引用，导致释放后重用，可能引发系统崩溃。

CVSS 7.8 · High EPSS 0.13% · P3

Possible ATT&CK Techniques 1 AI

T1211 · Exploitation for Stealth

Affected Version Matrix 18

VendorProduct Version RangeStatus
Linux Linux baa355fd331424526e742d41d9b90d5f9d10f716< bc2f5eabaaf60ec18da70b619a8fba1bfb7dea3a affected
baa355fd331424526e742d41d9b90d5f9d10f716< f87c08060818ebb19bafed37c38244538da25097 affected
baa355fd331424526e742d41d9b90d5f9d10f716< 6f5c272d71845a669e4c8ee5c72b376e29a0e6e5 affected
baa355fd331424526e742d41d9b90d5f9d10f716< be106f7855f03d3128ed0ce70ba74b484a90b473 affected
baa355fd331424526e742d41d9b90d5f9d10f716< e3dd774dbfd0b5bc2dbd0995221751b1234f8205 affected
baa355fd331424526e742d41d9b90d5f9d10f716< 10065fb891651d9541e7a5a2db84c1e656ece4f9 affected
baa355fd331424526e742d41d9b90d5f9d10f716< d640efe94d86d3be893d4c19220362546a637e90 affected
baa355fd331424526e742d41d9b90d5f9d10f716< e923bd21058ea02fd0dcd3549d151d143fd036e5 affected
… +10 more rows
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I. Basic Information for CVE-2026-74482

Vulnerability Information
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Vulnerability Title
mm/huge_memory: unlock i_mmap_rwsem before releasing after-split folios
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会开源的一个操作系统内核。 Linux kernel存在安全漏洞，该漏洞源于mm/huge_memory.c中的__folio_split()函数在拆分后释放folio时未正确持有inode引用，仍对mapping进行解引用，导致释放后重用，可能引发系统崩溃。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux baa355fd331424526e742d41d9b90d5f9d10f716 ~ bc2f5eabaaf60ec18da70b619a8fba1bfb7dea3a -
Linux Linux 4.8 -

II. Public POCs for CVE-2026-74482

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III. Intelligence Information for CVE-2026-74482

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Patches & Fixes for CVE-2026-74482 (8)

Same Patch Batch · Linux · 2026-08-15 · 845 CVEs total

CVE-2026-74280 10.0 CRITICAL crypto: marvell/octeontx - fix DMA cleanup using wrong loop index
CVE-2026-74279 10.0 CRITICAL crypto: cavium/cpt - fix DMA cleanup using wrong loop index
CVE-2026-72421 10.0 CRITICAL ipv4: fib: Don't ignore error route in local/main tables.
CVE-2026-72408 10.0 CRITICAL geneve: gate GRO hint in geneve_gro_complete() on gs->gro_hint
CVE-2026-72407 10.0 CRITICAL geneve: validate inner network offset in geneve_gro_complete()
CVE-2026-74475 10.0 CRITICAL vxlan: use neigh_ha_snapshot() in route_shortcircuit()
CVE-2026-74309 10.0 CRITICAL vdpa/octeon_ep: fix IRQ-to-ring mapping in interrupt handler
CVE-2026-72493 9.9 CRITICAL net: serialize netif_running() check in enqueue_to_backlog()
CVE-2026-72041 9.8 CRITICAL espintcp: use sk_msg_free_partial to fix partial send
CVE-2026-72477 9.8 CRITICAL fs/ntfs3: call _ntfs_bad_inode() when failing to rename
CVE-2026-72209 9.8 CRITICAL ntfs: validate attribute values on lookup
CVE-2026-72208 9.8 CRITICAL ntfs: add bounds check before accessing EA entries
CVE-2026-72206 9.8 CRITICAL ntfs: validate index block header more strictly
CVE-2026-72299 9.8 CRITICAL tipc: restrict socket queue dumps in enqueue tracepoints
CVE-2026-74434 9.8 CRITICAL rxrpc: Don't move a peeked OOB message onto the pending queue
CVE-2026-74433 9.8 CRITICAL rxrpc: Fix UAF in rxgk_issue_challenge()
CVE-2026-72473 9.8 CRITICAL xprtrdma: Decouple req recycling from RPC completion
CVE-2026-72472 9.8 CRITICAL nfs: use nfsi->rwsem to protect traversal of the file lock list
CVE-2026-74545 9.8 CRITICAL rtase: fix double free of multi-frag skb on DMA map failure
CVE-2026-72322 9.8 CRITICAL ipv6: mcast: Fix potential UAF in MLD delayed work

Showing top 20 of 845 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-74482

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