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CVE-2026-98844— netfs: clear post-EOF pagecache when extending a file via write

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.

在 Linux 内核中，以下漏洞已得到修复： netfs：通过 write 扩展文件时，清除 EOF 之后的页缓存 修复 netfs，使其能够清除由普通 write 操作在文件末尾（EOF）之后创建的“空洞”中的内容，前提是这些空洞中此前已通过内存映射（mmap）区域写入过脏数据。无论是缓冲写路径，还是非缓冲写/直接 I/O（DIO）路径，此前均未清除这些过时的页缓存。 在扩展性写操作之前，将跨越 EOF 的页框（folio）尾部清零。这是唯一可能包含通过 mmap 写入到 EOF 之后数据的页框，因为完全位于 E

AI Predicted 6.8 Difficulty: Moderate EPSS 0.16% · P4

Possible ATT&CK Techniques 1 AI

T1562.004

Affected Version Matrix 10

VendorProduct Version RangeStatus
Linux Linux 153a9961b551101cd38e94e26cd92fbfd198b19b< f8f7d86b3537e885ee620898a38b749fba8a8456 affected
153a9961b551101cd38e94e26cd92fbfd198b19b< 98f6a4589e0f5f6cf819b8dd45605efc481c06ce affected
153a9961b551101cd38e94e26cd92fbfd198b19b< a7036a73671fc83d299bc770710fe996d9fef9ca affected
153a9961b551101cd38e94e26cd92fbfd198b19b< 69bf14300b50631e7c2271289d347bbd1b19a06c affected
6.8 affected
< 6.8 unaffected
6.12.113≤ 6.12.* unaffected
6.18.56≤ 6.18.* unaffected
… +2 more rows
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I. Basic Information for CVE-2026-98844

Vulnerability Information
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Vulnerability Title
netfs: clear post-EOF pagecache when extending a file via write
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: netfs: clear post-EOF pagecache when extending a file via write Fix netfs to erase the contents of a hole created after the EOF by an ordinary write if dirty data has been previously left there by writes through an mmapped region. Neither the buffered nor the unbuffered/DIO write path clears that stale pagecache. Zero the tail of the folio straddling the EOF before an extending write. That is the only folio that can hold data written past the EOF through an mmap, as pages wholly beyond the EOF can't be faulted in. The folio is zeroed rather than dropped so a concurrent extending write can't lose data. Both write paths downgrade the i_rwsem to shared, so extending writes can run concurrently and the i_size read by the caller may be stale by the time the folio is locked. Re-read i_size under the folio lock and clamp the zeroed range up to it, so a racing write that already put data into the folio isn't clobbered. Wait for any writeback on the folio to finish before zeroing it so that the pagecache isn't modified while it may still be read by the transport during transmission. Honour IOCB_NOWAIT by returning -EAGAIN rather than blocking on the folio lock, on writeback, or in folio_mkclean()'s rmap walk when the folio is mapped. truncate_pagecache() can't be used here: it must be called with the i_rwsem held exclusively, but these write paths only hold it shared, and it would block unconditionally, breaking IOCB_NOWAIT. Callers that hold i_rwsem exclusively for the whole resize (truncate, setattr, fallocate, clone) exclude any genuine concurrent buffered writer, so staleness can instead be decided from the folio's dirty state, as pagecache_isize_extended() already does for filesystems that serialise writes against truncate/setattr via a single i_rwsem. Export netfs_clear_stale_post_isize() helper to handle such case. The helper is required by the CIFS client to fix generic/363.
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

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 153a9961b551101cd38e94e26cd92fbfd198b19b ~ f8f7d86b3537e885ee620898a38b749fba8a8456 -
Linux Linux 6.8 -

II. Public POCs for CVE-2026-98844

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III. Intelligence Information for CVE-2026-98844

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Patches & Fixes for CVE-2026-98844 (4)

Same Patch Batch · Linux · 2026-10-18 · 435 CVEs total

CVE-2026-98719 KVM: SEV: Nullify "have run CPUs" mask pointer when freeing it
CVE-2026-98732 Bluetooth: btintel: fix buffer over-read in btintel_hw_error()
CVE-2026-98731 Bluetooth: btintel_pcie: fix plen overflow in btintel_pcie_recv_frame()
CVE-2026-98730 Bluetooth: btintel_pcie: reject oversized TX packets in send_frame()
CVE-2026-98729 x86/mm: Don't apply va_align to hugetlb mappings on AMD F15h
CVE-2026-98728 tpm: fix off-by-four bounds check in tpm2_get_random()
CVE-2026-98727 nvme-multipath: set BLK_FEAT_ZONED only after the zone info is known
CVE-2026-98726 nvme-multipath: fix underflow in ANA log bounds checks
CVE-2026-98725 nvmet-auth: fix out-of-bounds write in nvmet_auth_challenge()
CVE-2026-98724 nvmet: pci-epf: reject too-short SGL segments
CVE-2026-98723 nvmet: copy the hostid into the ctrl before creating PR pc_refs
CVE-2026-98722 mtd: block2mtd: Fix divide error when erase_size is zero
CVE-2026-98721 mtd: rawnand: cadence: Initialize IRQ state before requesting IRQ
CVE-2026-98720 KVM: nVMX: Force MSR bitmap refresh if runtime eVMCS controls are modified
CVE-2026-98707 wifi: mac80211: shut down RX BA session timer on teardown
CVE-2026-98711 wifi: cw1200: fix TX padding OOB read leaking heap data to device
CVE-2026-98710 wifi: iwlegacy: 3945: free EEPROM data on remove
CVE-2026-98709 wifi: mac80211: count only matching reservations in reserved switch
CVE-2026-98712 KVM: arm64: vgic: Take a refcount on IRQs referenced by last_lr_irq
CVE-2026-98708 wifi: mac80211: keep paired old chanctx alive

Showing top 20 of 435 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-98844

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