CVE-2026-93100— fs/resctrl: Prevent use-after-free in rdtgroup_kn_put()
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.
以下是该漏洞描述信息的中文翻译： 在 Linux 内核中，已修复了以下漏洞： fs/resctrl：防止 rdtgroup_kn_put() 中的释放后使用（Use-After-Free, UAF）问题 结构体通过 进行引用计数管理。那些需要在休眠期间保持结构体有效性的调用者（例如在等待获取 时），会通过 获取引用，并通过 释放引用。 释放路径旨在充当后备的内存释放器：当计数降为零且该组已被标记为 时， 会释放该结构体。 批量拆卸路径 和 （由 resctrl 目录移除或 resctrl 文件系统卸载触发）充当主要
Possible ATT&CK Techniques 1 AI
T1210 · Exploitation of Remote ServicesAffected Version Matrix 16
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| Linux | Linux | b8511ccc75c033f6d54188ea4df7bf1e85778740< ae69f936e8ffed553d899ba4c02f8a7461a89e54 |
affected |
b8511ccc75c033f6d54188ea4df7bf1e85778740< 4c593c62c1499665baebbb41b70e2c9b7e947b86 |
affected | ||
b8511ccc75c033f6d54188ea4df7bf1e85778740< f5bcf539484d2d604c2f2330e09487ea090b21c7 |
affected | ||
d20edc0bca5577bab38acb5b190619c922ddebf8 |
affected | ||
1b006f8cbde9f3dabdfafe2ff7aa9f831ed5b625 |
affected | ||
40300f986e47dbc8f1d02e5080385f5cf9f85f70 |
affected | ||
b5a4949897ebada8132d54c93208989482503103 |
affected | ||
4.14.170< 4.15 |
affected | ||
| … +8 more rows | |||
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I. Basic Information for CVE-2026-93100
Vulnerability Information
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Vulnerability Title
fs/resctrl: Prevent use-after-free in rdtgroup_kn_put()
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved:
fs/resctrl: Prevent use-after-free in rdtgroup_kn_put()
A struct rdtgroup is reference counted via rdtgroup::waitcount. Callers that
need the structure to remain valid across a sleep (while waiting on acquiring
rdtgroup_mutex) take a reference with rdtgroup_kn_get() and release it with
rdtgroup_kn_put().
The release path is intended to serve as the fallback freer: if the count
drops to zero and the group has already been marked RDT_DELETED,
rdtgroup_kn_put() frees the structure.
The bulk teardown paths free_all_child_rdtgrp() and rmdir_all_sub() resulting
from a resctrl directory remove or resctrl fs unmount act as the primary
freer: they hold rdtgroup_mutex and free each rdtgroup whose waitcount is
zero, otherwise they set RDT_DELETED and leave the freeing to the last waiter.
These two freers race. rdtgroup_kn_put() commits waitcount == 0 with
atomic_dec_and_test() outside rdtgroup_mutex, then reads rdtgroup::flags.
Between those two operations a concurrent caller of free_all_child_rdtgrp()
or rmdir_all_sub() (which holds the mutex) can observe waitcount == 0 via
atomic_read(), call rdtgroup_remove(), and kfree() the structure.
The subsequent read of rdtgroup::flags in rdtgroup_kn_put() is then
a use-after-free, and the structure may even be freed twice if the freed
memory happens to satisfy the RDT_DELETED flag check.
Replace the bare atomic_dec_and_test() with atomic_dec_and_mutex_lock() so
that the decrement-to-zero takes rdtgroup_mutex before the count becomes
globally visible. The inspection of rdtgroup::flags then runs under the same
mutex held by the bulk freers, making the two paths mutually exclusive.
The common case where the count does not reach zero remains lock-free. Defer
kernfs_unbreak_active_protection() until after the mutex is dropped since
kernfs active protections functionally wrap rdtgroup_mutex. Remove resource
group, which in turn drops its kernfs reference, after kernfs protection is
restored.
[ bp: Split the commit messsages into smaller, easier-parseable paragraphs. ]
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
II. Public POCs for CVE-2026-93100
| # | POC Description | Source Link | Shenlong Link |
|---|
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Patches & Fixes for CVE-2026-93100 (3)
Same Patch Batch · Linux · 2026-09-17 · 600 CVEs total
| CVE-2026-92489 | 9.8 CRITICAL | xfrm: Fix skb double-free in xfrm_dev_direct_output() |
| CVE-2026-90173 | 9.8 CRITICAL | smb: smbdirect: free completion queues with ib_free_cq() |
| CVE-2026-90235 | 9.8 CRITICAL | sunrpc: xprtsock: annotate shared socket callbacks with READ_ONCE/WRITE_ONCE |
| CVE-2026-90104 | 9.8 CRITICAL | NFSv4.1: zero referring call lists before decoding |
| CVE-2026-90151 | 9.8 CRITICAL | NFSv4: remove callback IDR entry on client allocation failure |
| CVE-2026-90110 | 9.4 CRITICAL | inetpeer: randomize RB-tree node comparison using SipHash |
| CVE-2026-90230 | 9.1 CRITICAL | nvmet: fix heap out-of-bounds read in nvmet_auth_negotiate() |
| CVE-2026-90414 | 9.1 CRITICAL | IB/isert: reject PDUs declaring more data than was received |
| CVE-2026-90413 | 9.1 CRITICAL | IB/isert: reject login PDUs declaring more data than was received |
| CVE-2026-90367 | 8.8 HIGH | wifi: mt76: mt7996: hold dev->mt76.mutex while disabling tx worker in SER |
| CVE-2026-90329 | 8.8 HIGH | HID: synchronize input before cleaning up a failed probe |
| CVE-2026-93189 | 8.8 HIGH | HID: core: quiesce input in hid_hw_stop() to prevent use-after-free |
| CVE-2026-90286 | 8.8 HIGH | drm/amdgpu/gfx6: Use PFP on the compute queues too |
| CVE-2026-90357 | 8.8 HIGH | wifi: mt76: mt7915: unlink TWT flow if the MCU rejects the agreement |
| CVE-2026-90240 | 8.8 HIGH | iommu/vt-d: Flush context cache with correct SID when tearing down aliases |
| CVE-2026-93042 | 8.8 HIGH | dmaengine: dw-edma: Terminate all descriptors without callbacks |
| CVE-2026-90256 | 8.8 HIGH | Bluetooth: L2CAP: use proto_lock for l2cap_data to fix l2cap_disconn_ind |
| CVE-2026-90380 | 8.8 HIGH | wifi: mt76: mt792x: fix use-after-free in mt76_rx_poll_complete |
| CVE-2026-90381 | 8.8 HIGH | wifi: mt76: fix handling channel context with different bands in mt76_switch_vif_chanctx() |
| CVE-2026-90425 | 8.8 HIGH | iommu/tegra241-cmdqv: Require exactly one Stream ID for a vSID |
Showing top 20 of 600 CVEs. View all on vendor page → →
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Same vendor: Linux
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bpf: Reject dev-bound-only programs on other devices -
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V. Comments for CVE-2026-93100
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