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CVE-2026-93208— kasan: fix cache shrink race with CPU hotplug

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，已解决以下漏洞： kasan：修复 CPU 热插拔与缓存收缩之间的竞态条件 首先在所有在线 CPU 上调用 。每个回调函数将属于该缓存的对象从 移动到该 CPU 的 （收缩列表）中，以便稍后在任务上下文中释放这些对象。 在持有 的情况下调用清除隔离路径，但 并未持有该锁。因此，后者可能与 CPU 脱机操作发生竞态，具体如下： 留在 CPU1 的 中的对象未被返还给 slab 分配器。这可能导致 无法释放本应被清除的空 slab。如果 CPU1 保持脱机状态，后续的 也会跳过该列表，并报告缓存

AI Predicted 5.5 Difficulty: Theoretical EPSS 0.17% · P6

Possible ATT&CK Techniques 1 AI

T1690 · Prevent Command History Logging

Affected Version Matrix 12

VendorProduct Version RangeStatus
Linux Linux 07d067e4f2ceb72b9f681995cc53828caaba9e6e< 7cd164f0e1bab0f8dd125c92ed4f19bbd6b92a4a affected
07d067e4f2ceb72b9f681995cc53828caaba9e6e< 709c3646545e0a1f99a5816384c633f6552c5a98 affected
07d067e4f2ceb72b9f681995cc53828caaba9e6e< 30e8cb8598aa41b1b9f8803081d2ae5e5369c0f3 affected
07d067e4f2ceb72b9f681995cc53828caaba9e6e< 3119d58e4ef8719d669911d38a53fc00086ac48b affected
07d067e4f2ceb72b9f681995cc53828caaba9e6e< 8790303cbaac52a11dfed4aab261f8ea60682525 affected
5.19 affected
< 5.19 unaffected
6.6.157≤ 6.6.* unaffected
… +4 more rows
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I. Basic Information for CVE-2026-93208

Vulnerability Information
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Vulnerability Title
kasan: fix cache shrink race with CPU hotplug
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: kasan: fix cache shrink race with CPU hotplug kasan_quarantine_remove_cache() first invokes per_cpu_remove_cache() on all online CPUs. Each callback moves objects belonging to the cache from cpu_quarantine to the CPU's shrink_qlist, where they can later be freed from task context. kmem_cache_destroy() invokes the quarantine removal path while holding cpus_read_lock(), but kmem_cache_shrink() does not. The latter can therefore race with CPU offlining as follows: kmem_cache_shrink() CPU hotplug ------------------- ----------- on_each_cpu() CPU1 moves objects to CPU1's shrink_qlist on_each_cpu() returns CPU1 goes offline kasan_cpu_offline() drains cpu_quarantine leaves shrink_qlist untouched for_each_online_cpu() skips CPU1 The objects left on CPU1's shrink_qlist are not returned to the slab allocator. This may prevent kmem_cache_shrink() from releasing slabs that would otherwise become empty. If CPU1 remains offline, a later kmem_cache_destroy() also skips the list and can report that the cache still contains objects. An intermittent occurrence was observed with a virtio-9p filesystem. The mount and umount commands both returned 0, but the kernel logged the following during the userspace-triggered teardown: [ 2994.380134][ T111] BUG 9p-fcall-cache-1 (Tainted: G B ): Objects remaining on __kmem_cache_shutdown() [ 2994.381140][ T111] Object 0xff11000004361118 @offset=4376 [ 2994.381607][ T111] Allocated in p9_fcall_init+0x201/0x400 age=19564 cpu=1 pid=104 [ 2994.382591][ T111] p9_fcall_init+0x201/0x400 [ 2994.382810][ T111] p9_tag_alloc+0x12f/0x700 [ 2994.382982][ T111] p9_client_prepare_req+0x102/0x3e0 [ 2994.383165][ T111] p9_client_rpc+0x1ab/0xa50 [ 2994.383334][ T111] p9_client_getattr_dotl+0xb0/0x1a0 [ 2994.383515][ T111] v9fs_vfs_getattr_dotl+0x115/0x360 [ 2994.383719][ T111] vfs_getattr_nosec+0x22c/0x3a0 [ 2994.383910][ T111] vfs_statx+0xd7/0x170 [ 2994.384062][ T111] vfs_fstatat+0x45/0x80 [ 2994.384215][ T111] __do_sys_newfstatat+0x84/0xe0 [ 2994.384386][ T111] do_syscall_64+0x115/0x6a0 [ 2994.384566][ T111] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 2994.399720][ T111] WARNING: mm/slub.c:1244 at __kmem_cache_shutdown+0x363/0x500, CPU#0: busybox/111 [ 2994.405655][ T111] Call Trace: [ 2994.406325][ T111] kmem_cache_destroy+0x73/0x1b0 [ 2994.406630][ T111] p9_client_destroy+0x271/0x3c0 [ 2994.407210][ T111] v9fs_session_close+0x3c/0x260 [ 2994.407409][ T111] v9fs_kill_super+0x48/0x90 [ 2994.407584][ T111] deactivate_locked_super+0xa3/0x160 [ 2994.407778][ T111] cleanup_mnt+0x1dd/0x3e0 Thus, a successful umount left objects in the 9p fcall cache and prevented the cache from being destroyed cleanly. Per-CPU shrink_qlist storage exists for every possible CPU, and each list is protected by its own raw spinlock. Iterate over possible CPUs so that a list populated before its CPU went offline is drained as well. for_each_possible_cpu() can do more work than for_each_online_cpu(), but this change only affects CONFIG_KASAN_GENERIC kernels. The extra work is limited to cache shrink and cache destruction paths and does not affect the normal allocation/free fast path. It adds one raw-spinlock-protected scan of each possible CPU's shrink list. These lists are normally empty; a non-empty list is traversed to remove objects belonging to the cache being shrunk or destroyed.
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 07d067e4f2ceb72b9f681995cc53828caaba9e6e ~ 7cd164f0e1bab0f8dd125c92ed4f19bbd6b92a4a -
Linux Linux 5.19 -

II. Public POCs for CVE-2026-93208

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III. Intelligence Information for CVE-2026-93208

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Patches & Fixes for CVE-2026-93208 (5)

Same Patch Batch · Linux · 2026-09-24 · 234 CVEs total

CVE-2026-93207 9.8 CRITICAL SUNRPC: Zero rpc_gss_wire_cred at svcauth_gss_decode_credbody() entry
CVE-2026-97413 9.8 CRITICAL RDMA/rtrs-srv: Fix integer underflow in process_read and process_write
CVE-2026-93228 9.1 CRITICAL svcrdma: Reject Write/Reply chunks with segcount 0
CVE-2026-93793 8.8 HIGH wifi: iwlwifi: mvm: validate TX_CMD response layout
CVE-2026-93799 8.8 HIGH wifi: iwlwifi: mvm: validate sta_id in BA window status notif
CVE-2026-93790 8.8 HIGH wifi: iwlwifi: mvm: fix out-of-bounds tid_data access in BA notif
CVE-2026-93806 8.8 HIGH wifi: cfg80211: validate assoc response length before status and IE access
CVE-2026-97442 8.8 HIGH wifi: ath11k: fix invalid data access in ath11k_dp_rx_h_undecap_nwifi
CVE-2026-97409 8.8 HIGH nvme-fc: Do not cancel requests in io target before it is initialized
CVE-2026-97509 8.8 HIGH thunderbolt: Keep XDomain reference during the lifetime of a service
CVE-2026-93280 8.8 HIGH greybus: audio: bound the topology section sizes against the fetched size
CVE-2026-93284 8.8 HIGH drm/pagemap: dma-unmap pages before handling migration errors
CVE-2026-97451 8.4 HIGH ACPICA: Fix integer overflow in acpi_ex_opcode_3A_1T_1R() (mid_op)
CVE-2026-97452 8.4 HIGH ACPICA: Prevent adding invalid references
CVE-2026-97455 8.4 HIGH ACPICA: Fix use-after-free in acpi_ds_terminate_control_method()
CVE-2026-97450 8.4 HIGH ACPICA: validate handler object type in two places
CVE-2026-93827 8.4 HIGH virtio-fs: avoid double-free on failed queue setup
CVE-2026-97433 8.2 HIGH nvme: validate FDP configuration descriptor sizes
CVE-2026-93787 8.1 HIGH smb: client: bound dirent name against end of SMB response in cifs_filldir
CVE-2026-93224 8.1 HIGH svcrdma: Fix unmatched rn_unregister on failed accept

Showing top 20 of 234 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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