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CVE-2026-74307— ext4: validate donor file superblock early in EXT4_IOC_MOVE_EXT

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EXT4_IOC_MOVE_EXT ioctl未提前验证donor文件是否属于同一超级块，导致跨文件系统时产生循环锁依赖，可能导致死锁。

AI Predicted 5.6 Difficulty: Hard EPSS 0.21% · P10

Possible ATT&CK Techniques 1 AI

T1068 · Exploitation for Privilege Escalation

Affected Version Matrix 10

VendorProduct Version RangeStatus
Linux Linux fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a< 74796e886ca39fcb0d3fd36ea6a39c62784ab6fb affected
fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a< 29e07ec352f0ad06c833a18bf47d82c81f55544f affected
fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a< fb52013cad9e9b7d3a6a14ea1bcd841e41da7c6c affected
fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a< c143957520c6c9b5cd72e0de8b52b814f0c576fe affected
3.18 affected
< 3.18 unaffected
6.12.97≤ 6.12.* unaffected
6.18.57≤ 6.18.* unaffected
… +2 more rows
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I. Basic Information for CVE-2026-74307

Vulnerability Information
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Vulnerability Title
ext4: validate donor file superblock early in EXT4_IOC_MOVE_EXT
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: ext4: validate donor file superblock early in EXT4_IOC_MOVE_EXT Reject the EXT4_IOC_MOVE_EXT ioctl early if the donor file does not belong to the same superblock as the original file. Currently, this validation is performed inside ext4_move_extents() by mext_check_validity(), but only after lock_two_nondirectories() has already acquired the inode locks. When the donor fd refers to a file on a different filesystem (e.g., overlayfs), this late validation creates a circular lock dependency: CPU0 (overlayfs write) CPU1 (ext4 ioctl) ---- ---- inode_lock(ovl_inode) mnt_want_write_file(filp) sb_start_write(ext4_sb) [sb_writers] backing_file_write_iter() vfs_iter_write(real_file) file_start_write(real_file) sb_start_write(ext4_sb) [blocked by freeze] lock_two_nondirectories() inode_lock(ovl_inode) [blocked] With a concurrent freeze operation holding sb_writers write side, this forms a deadlock cycle: CPU0 waits for freeze to complete, freeze waits for CPU1's sb_writers reader to exit, CPU1 waits for CPU0's inode lock. Since EXT4_IOC_MOVE_EXT exchanges physical extents between two files, it fundamentally requires both files to reside on the same ext4 filesystem. Moving the superblock check before any lock acquisition is both semantically correct and eliminates the circular dependency by ensuring that cross-filesystem donor fds are rejected before sb_writers or inode locks are taken.
Source: CVE Program / CVE List V5
CVSS Information
N/A
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EXT4_IOC_MOVE_EXT ioctl未提前验证donor文件是否属于同一超级块，导致跨文件系统时产生循环锁依赖，可能导致死锁。
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 fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a ~ 74796e886ca39fcb0d3fd36ea6a39c62784ab6fb -
Linux Linux 3.18 -

II. Public POCs for CVE-2026-74307

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III. Intelligence Information for CVE-2026-74307

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Patches & Fixes for CVE-2026-74307 (2)

Same Patch Batch · Linux · 2026-08-15 · 844 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-2026-74475 10.0 CRITICAL vxlan: use neigh_ha_snapshot() in route_shortcircuit()
CVE-2026-72421 10.0 CRITICAL ipv4: fib: Don't ignore error route in local/main tables.
CVE-2026-74309 10.0 CRITICAL vdpa/octeon_ep: fix IRQ-to-ring mapping in interrupt handler
CVE-2026-72407 10.0 CRITICAL geneve: validate inner network offset in geneve_gro_complete()
CVE-2026-72408 10.0 CRITICAL geneve: gate GRO hint in geneve_gro_complete() on gs->gro_hint
CVE-2026-72493 9.9 CRITICAL net: serialize netif_running() check in enqueue_to_backlog()
CVE-2026-72319 9.8 CRITICAL ipvs: ensure inner headers in ICMP errors are in headroom
CVE-2026-72220 9.8 CRITICAL sunrpc: harden rq_procinfo lifecycle to prevent double-free
CVE-2026-72217 9.8 CRITICAL SUNRPC: Bound-check xdr_buf_to_bvec() stores before writing
CVE-2026-74384 9.8 CRITICAL nvme-multipath: fix flex array size in struct nvme_ns_head
CVE-2026-72299 9.8 CRITICAL tipc: restrict socket queue dumps in enqueue tracepoints
CVE-2026-72210 9.8 CRITICAL ntfs: fix off-by-one in mapping pairs decoding bounds checks
CVE-2026-72211 9.8 CRITICAL ntfs: grow index root value before reparent header update
CVE-2026-72317 9.8 CRITICAL SUNRPC: pin upper rpc_clnt across the TLS connect_worker
CVE-2026-72209 9.8 CRITICAL ntfs: validate attribute values on lookup
CVE-2026-74268 9.8 CRITICAL tcp: clear sock_ops cb flags before force-closing a child socket
CVE-2026-72207 9.8 CRITICAL ntfs: not change 0-byte $DATA attribute to non-resident
CVE-2026-74267 9.8 CRITICAL net/sched: sch_codel: Do not call qdisc_tree_reduce_backlog during peek before restoring q

Showing top 20 of 844 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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