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CVE-2026-89702— nfsd: size fh_verify server sockaddr slot by xpt_locallen

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，已修复以下漏洞： nfsd: 根据 xpt_locallen 确定 中服务器 sockaddr 插槽的大小 和 这两个跟踪点（tracepoints）声明服务器 sockaddr 插槽的大小时使用的是 ，但在填充数据时却从 复制数据，长度使用 ： 当 大于 时， 中的 会写入超出预留环形缓冲区插槽的范围（即发生缓冲区溢出）。反之，当 小于 时，插槽被过度分配，导致插槽中未被写入的尾部区域会向跟踪数据消费者泄露之前环形缓冲区中的旧内容。 “写入超出结束位置”的情况在 NFS/UDP 场景下是可

AI Predicted 3.9 Difficulty: Moderate

Possible ATT&CK Techniques 1 AI

T1105 · Ingress Tool Transfer

Affected Version Matrix 13

VendorProduct Version RangeStatus
Linux Linux 051382885552e12541cc0ebf82092be374a9ed2a< 95d064f9828a20ccca5ae90a17be3e2076f25272 affected
051382885552e12541cc0ebf82092be374a9ed2a< 7ff8d6363cffff45654ea85e319f7c0c54226012 affected
051382885552e12541cc0ebf82092be374a9ed2a< 719a10e3f5f868c3c4ac3cf3648c5775d12034bd affected
051382885552e12541cc0ebf82092be374a9ed2a< 71d068490098b1d23c63b2345e40675d3a1ca763 affected
dcbebc86850324fbe0a993ce352f0539cd98038a affected
62980365d6e894234b29f44fb2bfad4f7f8bb824 affected
5.15.154< 5.16 affected
6.0 affected
… +5 more rows
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I. Basic Information for CVE-2026-89702

Vulnerability Information
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Vulnerability Title
nfsd: size fh_verify server sockaddr slot by xpt_locallen
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: nfsd: size fh_verify server sockaddr slot by xpt_locallen The nfsd_fh_verify and nfsd_fh_verify_err tracepoints declare the server sockaddr slot sized by xpt_remotelen but fill it from xpt_local using xpt_locallen: TP_STRUCT__entry( ... __sockaddr(server, rqstp->rq_xprt->xpt_remotelen) ... ) TP_fast_assign( ... __assign_sockaddr(server, &rqstp->rq_xprt->xpt_local, rqstp->rq_xprt->xpt_locallen); ... ) When xpt_locallen exceeds xpt_remotelen, __assign_sockaddr's memcpy writes past the reserved ring-buffer slot. In the reverse direction (xpt_locallen < xpt_remotelen) the slot is oversized and the unwritten tail leaks prior ring-buffer contents to trace consumers. The write-past-end case is reachable on NFS/UDP. svc_xprt_set_remote() is only called from svc_tcp_accept() (net/sunrpc/svcsock.c) and from the RDMA connect path; svc_create_socket() for UDP calls only svc_xprt_set_local(), so xpt_remotelen stays 0 for the xprt's lifetime. Every fh_verify trace for an NFSv2/v3-over-UDP request then copies 16 or 28 bytes from xpt_local into a zero-byte slot. The other NFSD tracepoints that record the server address (NFSD_TRACE_PROC_CALL_FIELDS, NFSD_TRACE_PROC_RES_FIELDS, SVC_RQST_ENDPOINT_FIELDS) already size the server slot by xpt_locallen; nfsd_fh_verify and nfsd_fh_verify_err were the only exceptions. Fix by sizing the server slot with xpt_locallen so the declared slot matches the copy length. The client slot and its assignment already agree on xpt_remotelen and are left untouched.
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 051382885552e12541cc0ebf82092be374a9ed2a ~ 95d064f9828a20ccca5ae90a17be3e2076f25272 -
Linux Linux 6.0 -

II. Public POCs for CVE-2026-89702

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III. Intelligence Information for CVE-2026-89702

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Patches & Fixes for CVE-2026-89702 (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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