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CVE-2026-89682— nfsd: fix fcache_disposal UAF by inlining dispose state into nfsd_net

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： nfsd：通过将 dispose 状态内联到 中修复 的释放后使用（Use-After-Free, UAF）问题 将 操作延迟到 nfsd 服务线程中执行，通过每个网络命名空间（per-net）的 队列来实现，从而避免缩小器（shrinker）和垃圾回收（GC）工作线程承担关闭文件的开销（参见 commit ffb402596147）。然而，该队列位于一个单独分配的 结构体中，该结构体会在网络命名空间拆除（teardown）期间由 释放。此时，全局 shrinker、l

AI Predicted 5.7 Difficulty: Hard

Possible ATT&CK Techniques 1 AI

T1562

Affected Version Matrix 12

VendorProduct Version RangeStatus
Linux Linux 1463b38e7cf34d4cc60f41daff459ad807b2e408< ba0ee9e04b7a0356c28d5a2fe445db675d24e572 affected
1463b38e7cf34d4cc60f41daff459ad807b2e408< cadc9036d5a8209f89e7026ddba7cfb1c716b03c affected
1463b38e7cf34d4cc60f41daff459ad807b2e408< bbf13732f74351d21c5e0e8dd9bd8e1c48dc35d4 affected
e8f923e1e9fcc0832a12c8a2461792e5a9544c03 affected
3bc94fb44f10ef852723e1aeaac6794c5ab16aec affected
5.10.220< 5.11 affected
5.15.154< 5.16 affected
5.17 affected
… +4 more rows
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I. Basic Information for CVE-2026-89682

Vulnerability Information
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Vulnerability Title
nfsd: fix fcache_disposal UAF by inlining dispose state into nfsd_net
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: nfsd: fix fcache_disposal UAF by inlining dispose state into nfsd_net nfsd_file_dispose_list_delayed() defers fput() to nfsd service threads via a per-net freeme queue, preventing the shrinker and GC worker from bearing the cost of closing files (see ffb402596147). However, the queue lives in a separately-allocated struct nfsd_fcache_disposal that is freed by nfsd_free_fcache_disposal_net() during per-net teardown. The global shrinker, laundrette, and fsnotify callbacks can still be inside nfsd_file_dispose_list_delayed() dereferencing that pointer, causing a use-after-free. Inline the spinlock and freeme list directly into struct nfsd_net (as fcache_dispose_lock and fcache_dispose_list), eliminating the separately allocated struct nfsd_fcache_disposal entirely. These fields now have the same lifetime as the net namespace itself, so there is no dangling pointer to chase. nfsd_file_cache_start_net() now just initializes the inline fields and cannot fail due to allocation. nfsd_file_cache_shutdown_net() drains the inline list directly instead of freeing a separate struct. The alloc/free helpers are removed.
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 1463b38e7cf34d4cc60f41daff459ad807b2e408 ~ ba0ee9e04b7a0356c28d5a2fe445db675d24e572 -
Linux Linux 5.17 -

II. Public POCs for CVE-2026-89682

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III. Intelligence Information for CVE-2026-89682

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Other References for CVE-2026-89682 (3)

Same Patch Batch · Linux · 2026-09-11 · 431 CVEs total

CVE-2026-89491 ocfs2: cluster: don't sleep while holding o2hb_live_lock in o2hb_region_pin()
CVE-2026-89477 sctp: fix NULL deref on untransmitted RECONF completion
CVE-2026-89478 sctp: drop a chunk if its transport was removed
CVE-2026-89479 sctp: stop processing a packet once its association is deleted
CVE-2026-89480 nvme-tcp: reject a read that transferred too few bytes
CVE-2026-89482 nvme-tcp: do not accept C2HData based on blk_rq_payload_bytes() alone
CVE-2026-89481 nvme-tcp: fix host memory disclosure on R2T for a read command
CVE-2026-89483 nvme: zero the discard fallback page
CVE-2026-89484 lockd: fix NULL dereference on lockowner allocation failure
CVE-2026-89485 lockd: pin next file across nlm_inspect_file lock-drop
CVE-2026-89486 ipmi: Fix use-after-free of cmd_rcvr in _ipmi_destroy_user()
CVE-2026-89487 openvswitch: only skb_tx_error() a packet we are about to drop
CVE-2026-89488 openvswitch: Fix CT limit teardown use-after-free
CVE-2026-89489 openrisc: fix arbitrary kernel memory access via or1k_atomic syscall
CVE-2026-89500 ring-buffer: Make cpu_buffer::free_page a buffer_data_read_page
CVE-2026-89497 orangefs: skip leading spaces before parsing client debug masks
CVE-2026-89498 orangefs: fix double-free of trailer_buf on readdir copy failure
CVE-2026-89499 ring-buffer: Stop remote reader update when page swap fails
CVE-2026-89496 ocfs2: always run deallocs on copy-on-write completion
CVE-2026-89501 ring-buffer: Hold cpu_buffer::lock when resizing a subbuf

Showing top 20 of 431 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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