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CVE-2026-89699— nfsd: validate symlink target length in NFSv4 CREATE

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：在 NFSv4 CREATE 操作中验证符号链接目标长度的校验 函数在解析来自网络的 符号链接目标时，接受了无上限的 参数，这使得客户端能够强制触发高达 RPC 最大载荷大小（数 MiB）的 内存分配，且该内存块会一直保留到整个 COMPOUND 请求结束。尽管 VFS 层会对过长的目标名返回 错误，但此时内存分配已经发生。 修复方法是在早期阶段拒绝以下两种情况： 当 等于 0 时，返回 ； 当 大于 （即 ）时，返回 。 通过这种方式限制内存分配的大小，从而防止

AI Predicted 5.5 Difficulty: Moderate

Possible ATT&CK Techniques 1 AI

T1059 · Command and Scripting Interpreter

Affected Version Matrix 10

VendorProduct Version RangeStatus
Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< b24843ea3de1676b29902457b38507c95a80649b affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< 895a485cd3758031ef9993c0d53cf19ce8fb4ccc affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< 45ec115cbfecb4b3cfab7fca6f73d1b60696a25a affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< 041f57056e5fb9c80adc088269322d2c61074406 affected
2.6.12 affected
< 2.6.12 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-2026-89699

Vulnerability Information
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Vulnerability Title
nfsd: validate symlink target length in NFSv4 CREATE
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: nfsd: validate symlink target length in NFSv4 CREATE nfsd4_decode_create() accepts an unbounded cr_datalen from the wire for NF4LNK symlink targets, allowing a client to force a kmalloc of up to the maximum RPC payload size (several MiB) per COMPOUND op that persists until compound teardown. The VFS rejects oversized targets with ENAMETOOLONG, but the allocation has already occurred. Reject cr_datalen == 0 early with nfserr_inval and cr_datalen greater than NFS4_MAXPATHLEN (PATH_MAX) with nfserr_nametoolong to bound the allocation.
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 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 ~ b24843ea3de1676b29902457b38507c95a80649b -
Linux Linux 2.6.12 -

II. Public POCs for CVE-2026-89699

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III. Intelligence Information for CVE-2026-89699

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Other References for CVE-2026-89699 (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

V. Comments for CVE-2026-89699

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