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CVE-2026-74601— ring-buffer: Use current_context for safe per-CPU buffer swap

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： ring-buffer: 使用 current_context 实现安全的每 CPU 缓冲区交换 函数当前通过检查每 CPU（per-CPU）的提交计数器（committing counter），来判断缓冲区是否正在被写入，然后才执行缓冲区交换操作。然而，存在一个竞态窗口，可能导致该检查被绕过： 在单次写入操作期间（特别是在 内部），committing 计数器可能会暂时降至 0，从而形成一个竞态窗口：即使写入操作仍在进行中，交换操作也可能成功执行。这会导致缓冲区状态不一致

CVSS 7.8 · High EPSS 0.14% · P3

Possible ATT&CK Techniques 1 AI

T1068 · Exploitation for Privilege Escalation

Affected Version Matrix 18

VendorProduct Version RangeStatus
Linux Linux 4239c38fe0b3847e1e6d962c74b41b08ba0e2990< 26662bc8fced1d668fa1aa146eda085bfc67bd0b affected
4239c38fe0b3847e1e6d962c74b41b08ba0e2990< 6b524e6b234e45c7f5f90d13b042c6f57f80105c affected
4239c38fe0b3847e1e6d962c74b41b08ba0e2990< 597f279b7b4a06412e3d965e98cc36e181cdbede affected
4239c38fe0b3847e1e6d962c74b41b08ba0e2990< 22709117d9ae95e52673685f98caac7c356a8227 affected
4239c38fe0b3847e1e6d962c74b41b08ba0e2990< ad7e10c7ea89af45ac1bf1814855d45da472703d affected
4239c38fe0b3847e1e6d962c74b41b08ba0e2990< 5b926fb04cb9ef3156dcf88c69a59d3d1a1c4f9f affected
4239c38fe0b3847e1e6d962c74b41b08ba0e2990< 5e6e2a18c20e88167d414f666032792e8bf19b80 affected
4239c38fe0b3847e1e6d962c74b41b08ba0e2990< f27bdc43077e4fcb5557dfc315ee8d91e741f483 affected
… +10 more rows
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I. Basic Information for CVE-2026-74601

Vulnerability Information
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Vulnerability Title
ring-buffer: Use current_context for safe per-CPU buffer swap
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: ring-buffer: Use current_context for safe per-CPU buffer swap The ring_buffer_swap_cpu() function currently checks the per-CPU committing counter to determine if a buffer is actively being written to before performing the swap. However, there exists a race window where this check can be bypassed: ring_buffer_lock_reserve cpu_buffer = buffer->buffers[cpu]; // cpu_buffer_a rb_reserve_next_event rb_start_commit // inc committing if (unlikely(READ_ONCE(cpu_buffer->buffer) != buffer)) {...} __rb_reserve_next rb_move_tail rb_end_commit(cpu_buffer); // dec committing => 0 /* interrupt hits here, successfully swaps! */ local_inc(&cpu_buffer->committing); ring_buffer_unlock_commit cpu_buffer = buffer->buffers[cpu]; // cpu_buffer_b rb_commit rb_end_commit RB_WARN_ON(cpu_buffer, !local_read(&cpu_buffer->committing)) // triggers warning The committing counter can temporarily drop to 0 during a single write operation (within rb_move_tail), creating a window where swap can succeed even though the write is still in progress. This leads to inconsistent buffer state and triggers the RB_WARN_ON in rb_commit(). Replace the committing counter check with current_context checks, which are set at the entry of ring_buffer_lock_reserve() and remain valid throughout the entire write operation, providing a reliable indicator of buffer busy state during swap.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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 4239c38fe0b3847e1e6d962c74b41b08ba0e2990 ~ 26662bc8fced1d668fa1aa146eda085bfc67bd0b -
Linux Linux 4.5 -

II. Public POCs for CVE-2026-74601

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III. Intelligence Information for CVE-2026-74601

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Patches & Fixes for CVE-2026-74601 (8)

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-2026-74587 9.8 CRITICAL sctp: fix use-after-free of cached ASCONF chunk
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-2026-74669 9.8 CRITICAL ipvs: clear IPv4 options after rebasing tunnel ICMP errors
CVE-2026-74611 9.8 CRITICAL tls: rx: restore msg_iter before TLS 1.3 optimistic retry
CVE-2026-74608 9.8 CRITICAL smb: client: Fix use-after-free in cifs_try_adding_channels()
CVE-2026-74588 9.8 CRITICAL sctp: keep chunk->transport in step with the list it is queued on
CVE-2026-74688 9.8 CRITICAL sctp: clear control chunk transport if it is being removed
CVE-2026-74617 9.8 CRITICAL dibs: initialise dibs->lock in dibs_dev_alloc()
CVE-2026-74723 9.8 CRITICAL btrfs: lzo: reject inline extents without valid headers
CVE-2026-74727 9.8 CRITICAL ovpn: skip rehash for peers already removed from by_id
CVE-2026-74586 9.8 CRITICAL sctp: clear new_transport when removing a peer
CVE-2026-74597 9.8 CRITICAL ip6_tunnel: clear skb2->cb[] in ip6ip6_err()
CVE-2026-74616 9.8 CRITICAL xdp: reject clones that overrun skb_shared_info tailroom
CVE-2026-74730 9.8 CRITICAL NFS: Pin the 'struct nfs_server' during a FREE_STATEID call
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

V. Comments for CVE-2026-74601

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