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CVE-2026-98021— net: reject oversized tx_queue_len at netlink parse time

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.

以下是该漏洞修复说明的中文翻译： 在 Linux 内核中，已解决以下漏洞： 网络：在 Netlink 解析阶段拒绝过大的 tx_queue_len 值 函数会直接将 赋值给 ，而未经过 函数处理。因此，使用命令 创建的设备会绕过 S16_MAX（有符号 16 位整数最大值）的上限限制，并在 pfifo_fast、tun 和 tap 驱动程序中触发过大的环形缓冲区（ring）分配。veth 对端嵌套逻辑（ ）以及“在现有设备上执行 RTM_NEWLINK”的路径也会触及相同的潜在问题点。 现在在 （Netlink 属

AI Predicted 4.3 Difficulty: Easy EPSS 0.18% · P7

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 10

VendorProduct Version RangeStatus
Linux Linux 38f7b870d4a6a5d3ec21557e849620cb7d032965< 45ca9f59b6c7ea70e0a17054902b8a556913db34 affected
38f7b870d4a6a5d3ec21557e849620cb7d032965< 2fd0880f0272ec022906a05587fd91416ebecc38 affected
38f7b870d4a6a5d3ec21557e849620cb7d032965< a638a2625aa83160a394abe8e8b2e524a80c771b affected
38f7b870d4a6a5d3ec21557e849620cb7d032965< 1aa9e143bf51405665a793d4cc925e1c4f0c5922 affected
2.6.23 affected
< 2.6.23 unaffected
6.12.111≤ 6.12.* unaffected
6.18.53≤ 6.18.* unaffected
… +2 more rows
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I. Basic Information for CVE-2026-98021

Vulnerability Information
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Vulnerability Title
net: reject oversized tx_queue_len at netlink parse time
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: net: reject oversized tx_queue_len at netlink parse time rtnl_create_link() assigns IFLA_TXQLEN directly to dev->tx_queue_len without going through netif_change_tx_queue_len(), so a device created with "ip link add ... txqueuelen 500000" bypasses the S16_MAX cap and still triggers the oversized ring allocations in pfifo_fast, tun and tap. The veth peer nest (rtnl_nla_parse_ifinfomsg()) and the RTM_NEWLINK-on-existing-device path reach the same sinks. Enforce the cap in ifla_policy instead: IFLA_TXQLEN becomes NLA_POLICY_FULL_RANGE(NLA_U32, &txqlen_range) with txqlen_range = { .min = 0, .max = S16_MAX }. All netlink consumers parse against this policy - rtnl_setlink(), rtnl_newlink() (create and change), and the veth peer nest - so every netlink path is capped at parse time and rejects the attribute with -ERANGE plus a proper "integer out of range" extack message before any device state is modified (the RTM_SETLINK half-application wart is gone with it). Document the bound in the rt-link.yaml netlink spec. Conditions to recreate the bug: - CONFIG_NET_SCHED=y, CONFIG_VETH=y, CONFIG_USER_NS=y, CONFIG_NET_NS=y. - Unprivileged user in a fresh user+net namespace (unshare -Urn): ip link add v0 txqueuelen 500000 type veth peer name v1 -> on the fixed kernel this is rejected with -ERANGE ("integer out of range" extack) instead of installing an oversized tx_queue_len that later inflates pfifo_fast/tun/tap ring allocations. - ip link set v0 txqueuelen 500000 is likewise rejected at parse time.
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 38f7b870d4a6a5d3ec21557e849620cb7d032965 ~ 45ca9f59b6c7ea70e0a17054902b8a556913db34 -
Linux Linux 2.6.23 -

II. Public POCs for CVE-2026-98021

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III. Intelligence Information for CVE-2026-98021

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Patches & Fixes for CVE-2026-98021 (4)

Same Patch Batch · Linux · 2026-09-25 · 372 CVEs total

CVE-2026-100075 9.8 CRITICAL RDMA/srpt: Fix srpt_alloc_rw_ctxs() unwind counters
CVE-2026-97555 8.8 HIGH smb: client: fix heap overflow in DACL owner/group rewrite
CVE-2026-97957 8.8 HIGH net: hinic: fix mailbox segment buffer overflow
CVE-2026-97527 8.8 HIGH scsi: qla2xxx: Serialize NVMe unsol ctx list with a per-fcport lock
CVE-2026-97528 8.8 HIGH scsi: qla2xxx: Unlink NVMe unsol ctx before freeing on LS reject error
CVE-2026-98115 8.8 HIGH ksmbd: safely drain sessions during logoff
CVE-2026-97525 8.2 HIGH x86/mm/pat: Allocate split page tables as kernel page tables
CVE-2026-98069 8.1 HIGH net/rds: acquire the fastpath locks in rds_conn_shutdown()
CVE-2026-97573 8.1 HIGH bnxt_en: Handle buffer allocation failure in bnxt_rx_ring_reset()
CVE-2026-97570 8.1 HIGH bnxt_en: Bound SW TPA IDs to prevent crashes
CVE-2026-98130 8.1 HIGH sctp: fix a TOCTOU race in SCTP_CMD_TIMER_START
CVE-2026-98070 8.1 HIGH net/rds: acquire RDS_IN_XMIT in rds_tcp_reset_callbacks()
CVE-2026-98002 7.8 HIGH iommu/amd: Fix ineffective error check in nested domain allocation
CVE-2026-97575 7.8 HIGH media: v4l2-ctrls: validate AV1 tile counts
CVE-2026-97576 7.8 HIGH media: v4l2-ctrls: validate HEVC tile counts
CVE-2026-97941 7.8 HIGH mm/slab: take n->list_lock in __slab_try_return_freelist() to avoid race
CVE-2026-98112 7.8 HIGH ksmbd: fix listener task lifetime on netdev events
CVE-2026-97937 7.8 HIGH ftrace: fork: Initialize function graph state before copy_exec_state()
CVE-2026-97580 7.8 HIGH media: rkvdec: bound HEVC tile loops and PPS id to the array capacity
CVE-2026-97940 7.8 HIGH ipv6: fix fib6 walker UAF on seq stop

Showing top 20 of 372 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-98021

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