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CVE-2026-89707— nfsd: release path refs on follow_down() error

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，以下漏洞已得到解决： nfsd：在 follow_down() 出错时释放路径引用 在调用 之前，会先通过 和 初始化一个本地 并获取引用。然而，当 返回负值时，错误处理分支直接跳转至 标签，而未释放之前获取的引用： 在任何错误情况下都不会丢弃调用方在入口时获取的引用。例如，如果在跨越挂载点前 失败， 保持不变，因此入口处通过 和 获取的引用在调用后依然存在。 在 中的其他所有提前退出分支（包括跨命名空间返回、 错误，以及交换操作成功后的尾部处理）都已经调用了 ；唯独 这个分支漏掉了该调用。

AI Predicted 5.9 Difficulty: Easy

Affected Version Matrix 10

VendorProduct Version RangeStatus
Linux Linux cc53ce53c86924bfe98a12ea20b7465038a08792< 194316df81263519156ebe714c4a286bee00e5be affected
cc53ce53c86924bfe98a12ea20b7465038a08792< 467d56fd3ff57447a790c6dc3ede2d02a947d224 affected
cc53ce53c86924bfe98a12ea20b7465038a08792< 2bc4343308d85ee4e0dd3877b384306c96f114c2 affected
cc53ce53c86924bfe98a12ea20b7465038a08792< 6cba08dc1922140d260cfeb30bbda4ee1bf869d8 affected
2.6.38 affected
< 2.6.38 unaffected
6.12.109≤ 6.12.* unaffected
6.18.50≤ 6.18.* unaffected
… +2 more rows
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I. Basic Information for CVE-2026-89707

Vulnerability Information
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Vulnerability Title
nfsd: release path refs on follow_down() error
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: nfsd: release path refs on follow_down() error nfsd_cross_mnt() initializes a local struct path with mntget() and dget() before calling follow_down(). On a negative return the error arm jumps to out without releasing those references: err = follow_down(&path, follow_flags); if (err < 0) goto out; follow_down() never drops the caller's entry-time refs on any error sub-case; for example a pre-cross d_manage() failure leaves path untouched, so the mntget()/dget() taken on entry survive the call. Every other early-exit arm in nfsd_cross_mnt() (other-namespace return, IS_ERR(exp2), and the success tail after the swap) already calls path_put(&path); the err < 0 arm is the lone omission. The leak inflates mnt_count and d_count on each failed cross-mount, blocking umount and pinning dentries against the shrinker, and is reachable by any authenticated NFS client through nfsd_lookup_dentry or the NFSv4 READDIR encode path. Fix by calling path_put(&path) before the goto out in the err < 0 arm so the entry-time refs are released on all follow_down() error returns.
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 cc53ce53c86924bfe98a12ea20b7465038a08792 ~ 194316df81263519156ebe714c4a286bee00e5be -
Linux Linux 2.6.38 -

II. Public POCs for CVE-2026-89707

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III. Intelligence Information for CVE-2026-89707

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Patches & Fixes for CVE-2026-89707 (4)

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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