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CVE-2026-89771— ring-buffer: Fix subbuf resize race with ring buffer readers

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，以下漏洞已得到修复： 环形缓冲区：修复子缓冲区（subbuf）调整大小与环形缓冲区读取器之间的竞态条件 的 在 和 中是无锁读取的，而它可能同时被 调整大小，从而导致竞态条件。 修复措施： 不再使用 ，改为在 和 中使用 。 在 中，即使 为真，仍存在与缓冲区修改产生竞态的可能性。因此，通过持有 的互斥锁，与任何待处理的环形缓冲区阶数（order）修改进行同步。 字段现已变得无实际用途，予以移除。 同时，引入新的访问器函数： - 和 ：返回可用于存储事件的可用空间大小； - ：返回实际的子缓

AI Predicted 3.5 Difficulty: Theoretical

Affected Version Matrix 10

VendorProduct Version RangeStatus
Linux Linux f9b94daa542a8d2532f0930f01cd9aec2d19621b< 6d666f0b8b36c0765cf19fbe6de5a7ba5a73aad9 affected
f9b94daa542a8d2532f0930f01cd9aec2d19621b< 50f4a793c4ff24826efb0ac700989a5063cc53df affected
f9b94daa542a8d2532f0930f01cd9aec2d19621b< 0c7c517827a453128a8f58bfd849546a29813b27 affected
f9b94daa542a8d2532f0930f01cd9aec2d19621b< 8a5f63637890f03177146efddaba5ec7a1b4d61f affected
6.8 affected
< 6.8 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-2026-89771

Vulnerability Information
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Vulnerability Title
ring-buffer: Fix subbuf resize race with ring buffer readers
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: ring-buffer: Fix subbuf resize race with ring buffer readers trace_buffer subbuf_size is read lockless in ring_buffer_read_page() and ring_buffer_read_start(), while it can simultaneously be resized with ring_buffer_subbuf_order_set(). Instead of trace_buffer::subbuf_size, use bpage::order in ring_buffer_read_start() and ring_buffer_read_page(). In ring_buffer_read_start(), even with resize_disabled, there is still a possibility of a race with a buffer modification. Hold the trace_buffer mutex to synchronise with any pending ring buffer order modification. trace_buffer::subbuf_size is now actually useless, remove it. Also, create accessors rb_subbuf_capacity() and rb_page_capacity() which return the actual size available for storing events, while rb_subbuf_size() returns the actual subbuf page-size.
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 f9b94daa542a8d2532f0930f01cd9aec2d19621b ~ 6d666f0b8b36c0765cf19fbe6de5a7ba5a73aad9 -
Linux Linux 6.8 -

II. Public POCs for CVE-2026-89771

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III. Intelligence Information for CVE-2026-89771

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Other References for CVE-2026-89771 (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-2026-89771

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