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CVE-2026-89690— nfsd: defer vfree of compound ops to fix rpc_status UAF

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，已解决以下漏洞： nfsd：推迟对复合操作（compound ops）的 vfree，以修复 rpc_status 中的释放后使用（UAF）问题 问题描述： rpc_status 的 netlink 函数在 保护下遍历所有正在处理的 请求，并针对 NFSv4 请求从 中读取操作码（opnums）。然而， 是一个通过 vmalloc 分配的独立缓冲区，它在每个复合操作结束时由 中的 同步释放。 中的 仅固定了 结构体本身（该结构体通过 释放），但没有任何机制在 RCU 宽限期内推迟对 缓冲区的

AI Predicted 5.9 Difficulty: Moderate

Possible ATT&CK Techniques 1 AI

T1218 · System Binary Proxy Execution

Affected Version Matrix 10

VendorProduct Version RangeStatus
Linux Linux bd9d6a3efa9709e653aafbeb859289feccb8e70c< 48f72aff24f7a7329209dc6cbc27c869f3e3595c affected
bd9d6a3efa9709e653aafbeb859289feccb8e70c< 6703199f4d7e7f37d6a726a849eb358e8fae72fb affected
bd9d6a3efa9709e653aafbeb859289feccb8e70c< 19413ccc45070a7270b9e25c2a258daf7f91de42 affected
bd9d6a3efa9709e653aafbeb859289feccb8e70c< fca26a3fc19ed02278aa2a150af82d43db0302cb affected
6.7 affected
< 6.7 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-2026-89690

Vulnerability Information
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Vulnerability Title
nfsd: defer vfree of compound ops to fix rpc_status UAF
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: nfsd: defer vfree of compound ops to fix rpc_status UAF The rpc_status netlink dumpit walks every in-flight svc_rqst under rcu_read_lock and, for NFSv4 requests, reads opnums out of args->ops[]. But args->ops is a separate vmalloc buffer freed synchronously by vfree() in nfsd4_release_compoundargs() at the end of every compound. The dumpit's rcu_read_lock pins the svc_rqst struct itself (freed via kfree_rcu), but nothing defers the vfree of the ops buffer across the RCU grace period. A concurrent compound completion can therefore free the buffer while the dumpit is reading it — a use-after-free on vmalloc memory. The trailing seqcount recheck (smp_load_acquire of rq_status_counter) cannot undo a load that already retired against freed memory. Fix by replacing vfree(args->ops) with kvfree_rcu_mightsleep(), which defers the free until after an RCU grace period. This makes the existing rcu_read_lock in the dumpit sufficient to protect the read. The tradeoff is that completed compound ops buffers (up to 200 * sizeof(struct nfsd4_op)) persist in memory slightly longer, across one grace period, before being reclaimed.
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 bd9d6a3efa9709e653aafbeb859289feccb8e70c ~ 48f72aff24f7a7329209dc6cbc27c869f3e3595c -
Linux Linux 6.7 -

II. Public POCs for CVE-2026-89690

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III. Intelligence Information for CVE-2026-89690

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Patches & Fixes for CVE-2026-89690 (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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