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CVE-2026-74696— tcp: fix TFO max_qlen accounting across reuseport migration

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： tcp: 修复在 SO_REUSEPORT 迁移过程中 TFO max_qlen 的计数问题 TCP_FASTOPEN 的 max_qlen（最大队列长度）在侦听器迁移后不再准确，导致实际接受的待处理 Fast Open 请求数量远超配置的限制。 该问题仅在启用 SO_REUSEPORT 的侦听器迁移场景中出现。当关闭一个侦听器时，其仍待处理的 TFO（TCP Fast Open）子连接会被移交到一个存活的侦听器上。 在子连接创建时， 会对 进行计数（增加）；在握手完成时，

CVSS 7.5 · High EPSS 0.49% · P40

Possible ATT&CK Techniques 1 AI

T1498 · Network Denial of Service

Affected Version Matrix 16

VendorProduct Version RangeStatus
Linux Linux 54b92e84193749c9968aff2dd46e3b0f42643e18< e98f0d80b9cccb5f828425d2004f9686e7d1ae24 affected
54b92e84193749c9968aff2dd46e3b0f42643e18< b6247e0f96bd825ffb2005257f6177b5e642dee6 affected
54b92e84193749c9968aff2dd46e3b0f42643e18< 585fc5247d14939a561056aa2addd9b7c2b1f670 affected
54b92e84193749c9968aff2dd46e3b0f42643e18< 6e10ee56524a26b250229ad348637825646ddb88 affected
54b92e84193749c9968aff2dd46e3b0f42643e18< a66e869cf0c90c1e47ae75f72b6482acbfc808ff affected
54b92e84193749c9968aff2dd46e3b0f42643e18< d974618b2097453778389d385e3741629c40e0a3 affected
54b92e84193749c9968aff2dd46e3b0f42643e18< a0ab2ba83e35159d81cec830a92e885ecf8139be affected
5.14 affected
… +8 more rows
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I. Basic Information for CVE-2026-74696

Vulnerability Information
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Vulnerability Title
tcp: fix TFO max_qlen accounting across reuseport migration
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: tcp: fix TFO max_qlen accounting across reuseport migration A listener's TCP_FASTOPEN max_qlen stops being accurate and lets through far more pending Fast Open requests than it was configured for. This only shows up with SO_REUSEPORT listener migration, where closing a listener hands its still-pending TFO children over to a surviving one. fastopenq.qlen is charged in tcp_fastopen_create_child() when the child is created and uncharged in reqsk_fastopen_remove() when the handshake completes. The uncharge follows rsk_listener of the request the child points at, and inet_reqsk_clone() has repointed the child at a new request owned by the new listener, so the ++ and the -- land on two different sockets. The new listener's qlen drifts negative and its limit no longer binds. Charge the new listener during migration, like reqsk_queue_migrated() already does for queue->young and queue->qlen.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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 54b92e84193749c9968aff2dd46e3b0f42643e18 ~ e98f0d80b9cccb5f828425d2004f9686e7d1ae24 -
Linux Linux 5.14 -

II. Public POCs for CVE-2026-74696

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III. Intelligence Information for CVE-2026-74696

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Patches & Fixes for CVE-2026-74696 (7)

Same Patch Batch · Linux · 2026-08-22 · 150 CVEs total

CVE-2026-74705 10.0 CRITICAL udp: fix potential use-after-free in tunnel segmentation
CVE-2026-74612 10.0 CRITICAL veth: fix skb length accounting after XDP frag adjustment
CVE-2026-74616 9.8 CRITICAL xdp: reject clones that overrun skb_shared_info tailroom
CVE-2026-74617 9.8 CRITICAL dibs: initialise dibs->lock in dibs_dev_alloc()
CVE-2026-74608 9.8 CRITICAL smb: client: Fix use-after-free in cifs_try_adding_channels()
CVE-2026-74597 9.8 CRITICAL ip6_tunnel: clear skb2->cb[] in ip6ip6_err()
CVE-2026-74669 9.8 CRITICAL ipvs: clear IPv4 options after rebasing tunnel ICMP errors
CVE-2026-74688 9.8 CRITICAL sctp: clear control chunk transport if it is being removed
CVE-2026-74662 9.8 CRITICAL inet: frags: publish queues before arming timer
CVE-2026-74591 9.8 CRITICAL mm/filemap: __filemap_add_folio() restore index before retrying
CVE-2026-74628 9.8 CRITICAL net/x25: fix use-after-free of the socket by its timers
CVE-2026-74611 9.8 CRITICAL tls: rx: restore msg_iter before TLS 1.3 optimistic retry
CVE-2026-74587 9.8 CRITICAL sctp: fix use-after-free of cached ASCONF chunk
CVE-2026-74588 9.8 CRITICAL sctp: keep chunk->transport in step with the list it is queued on
CVE-2026-74586 9.8 CRITICAL sctp: clear new_transport when removing a peer
CVE-2026-74723 9.8 CRITICAL btrfs: lzo: reject inline extents without valid headers
CVE-2026-74730 9.8 CRITICAL NFS: Pin the 'struct nfs_server' during a FREE_STATEID call
CVE-2026-74727 9.8 CRITICAL ovpn: skip rehash for peers already removed from by_id
CVE-2026-74712 9.3 CRITICAL vdpa/mlx5: Fix buffer length in create_direct_keys()
CVE-2026-74665 9.1 CRITICAL net: fix skb length accounting after generic XDP frag adjustment

Showing top 20 of 150 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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