CVE-2026-97992— vhost-vdpa: protect config_ctx from being freed under the config callback
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： vhost-vdpa：在配置回调期间防止 config_ctx 被释放 会加载 并发送信号，但未获取引用计数且未持有锁： 会替换该字段，并释放旧上下文通常的最后一个引用： 会释放最后的 并立即释放上下文，不经过 RCU 宽限期（RCU grace period），因此，已经加载了该指针的回调将继续解引用已释放的内存。这两侧共享无锁： 在 下运行，而父组件从其自己的中断或工作队列上下文调用回调。 这并非由 commit f6bbf0010ba0（“vhost-vdpa: fi
Possible ATT&CK Techniques 1 AI
T1203 · Exploitation for Client ExecutionAffected Version Matrix 10
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| Linux | Linux | 776f395004d829bbbf18c159ed9beb517a208c71< bf35c8948ab7a3eaf1f724fa1e870e3f73a1749b |
affected |
776f395004d829bbbf18c159ed9beb517a208c71< 5a075ee2398929d5cc1393666f219c35332becb1 |
affected | ||
776f395004d829bbbf18c159ed9beb517a208c71< f4a93f15ed1c8406ba5c8e5b28cafacb2b3bcd11 |
affected | ||
776f395004d829bbbf18c159ed9beb517a208c71< 62be4e3e5f5f947fbf765b914cebdc478f715d12 |
affected | ||
5.8 |
affected | ||
< 5.8 |
unaffected | ||
6.12.111≤ 6.12.* |
unaffected | ||
6.18.53≤ 6.18.* |
unaffected | ||
| … +2 more rows | |||
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I. Basic Information for CVE-2026-97992
Vulnerability Information
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Vulnerability Title
vhost-vdpa: protect config_ctx from being freed under the config callback
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved:
vhost-vdpa: protect config_ctx from being freed under the config callback
vhost_vdpa_config_cb() loads v->config_ctx and signals it without taking
a reference and without holding any lock:
struct eventfd_ctx *config_ctx = v->config_ctx;
if (config_ctx)
eventfd_signal(config_ctx);
VHOST_VDPA_SET_CONFIG_CALL replaces that field and drops what is normally
the last reference to the old context:
swap(ctx, v->config_ctx);
if (ctx)
eventfd_ctx_put(ctx);
eventfd_ctx_put() drops the last kref and frees the context immediately,
with no RCU grace period, so a callback that has already loaded the
pointer goes on to dereference freed memory. The two sides share no
lock: the ioctl runs under vhost_dev.mutex, while the parent invokes the
callback from its own interrupt or workqueue context.
This is not the reopen refcount underflow fixed by commit f6bbf0010ba0
("vhost-vdpa: fix use-after-free of v->config_ctx"), which was about
vhost_vdpa_config_put() leaving a stale pointer behind. Here the pointer
is maintained correctly and it is the read side that is unprotected.
With VDUSE as the parent this is reachable from userspace with access to
/dev/vduse (root by default). VDUSE_DEV_INJECT_CONFIG_IRQ queues
dev->inject, and vduse_dev_irq_inject() runs the callback under VDUSE's
own dev->irq_lock, which vhost does not hold. vduse_dev_reset() does
flush_work(&dev->inject), but VHOST_VDPA_SET_CONFIG_CALL never goes
through reset, so an inject already in flight is not waited for. A
process that injects config interrupts on the VDUSE fd while another
thread swaps the call fd on the vhost-vdpa fd hits it in seconds:
BUG: KASAN: slab-use-after-free in native_queued_spin_lock_slowpath
Read of size 4 at addr ffff888107d21808 by task kworker/u17:1/2993
Workqueue: vduse-irq vduse_dev_irq_inject
Call Trace:
native_queued_spin_lock_slowpath+0x97/0x5b0
_raw_spin_lock_irqsave+0xd4/0xe0
eventfd_signal_mask+0x69/0x120
vhost_vdpa_config_cb+0x34/0x50
vduse_dev_irq_inject+0x46/0x60
process_one_work+0x468/0x950
Allocated by task 2992:
do_eventfd+0x50/0x200
__x64_sys_eventfd2+0x2e/0x40
Freed by task 2992:
eventfd_ctx_put+0xb9/0xc0
vhost_vdpa_unlocked_ioctl+0x116c/0x2190
Add a spinlock covering every access to config_ctx, so the callback
either signals a context that is still alive or observes NULL, and the
put happens only once no callback can reach the old value.
Clearing the parent's callback before the put would not be enough: of the
in-tree set_config_cb() implementations only VDUSE takes a lock, the rest
store the pointer unlocked, so that would not order against an in-flight
invocation.
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-2026-97992
| # | POC Description | Source Link | Shenlong Link |
|---|
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Patches & Fixes for CVE-2026-97992 (4)
Same Patch Batch · Linux · 2026-09-25 · 372 CVEs total
| CVE-2026-100075 | 9.8 CRITICAL | RDMA/srpt: Fix srpt_alloc_rw_ctxs() unwind counters |
| CVE-2026-97555 | 8.8 HIGH | smb: client: fix heap overflow in DACL owner/group rewrite |
| CVE-2026-97957 | 8.8 HIGH | net: hinic: fix mailbox segment buffer overflow |
| CVE-2026-97527 | 8.8 HIGH | scsi: qla2xxx: Serialize NVMe unsol ctx list with a per-fcport lock |
| CVE-2026-97528 | 8.8 HIGH | scsi: qla2xxx: Unlink NVMe unsol ctx before freeing on LS reject error |
| CVE-2026-98115 | 8.8 HIGH | ksmbd: safely drain sessions during logoff |
| CVE-2026-97525 | 8.2 HIGH | x86/mm/pat: Allocate split page tables as kernel page tables |
| CVE-2026-98069 | 8.1 HIGH | net/rds: acquire the fastpath locks in rds_conn_shutdown() |
| CVE-2026-97573 | 8.1 HIGH | bnxt_en: Handle buffer allocation failure in bnxt_rx_ring_reset() |
| CVE-2026-97570 | 8.1 HIGH | bnxt_en: Bound SW TPA IDs to prevent crashes |
| CVE-2026-98130 | 8.1 HIGH | sctp: fix a TOCTOU race in SCTP_CMD_TIMER_START |
| CVE-2026-98070 | 8.1 HIGH | net/rds: acquire RDS_IN_XMIT in rds_tcp_reset_callbacks() |
| CVE-2026-97941 | 7.8 HIGH | mm/slab: take n->list_lock in __slab_try_return_freelist() to avoid race |
| CVE-2026-97575 | 7.8 HIGH | media: v4l2-ctrls: validate AV1 tile counts |
| CVE-2026-97576 | 7.8 HIGH | media: v4l2-ctrls: validate HEVC tile counts |
| CVE-2026-98002 | 7.8 HIGH | iommu/amd: Fix ineffective error check in nested domain allocation |
| CVE-2026-98112 | 7.8 HIGH | ksmbd: fix listener task lifetime on netdev events |
| CVE-2026-97937 | 7.8 HIGH | ftrace: fork: Initialize function graph state before copy_exec_state() |
| CVE-2026-97580 | 7.8 HIGH | media: rkvdec: bound HEVC tile loops and PPS id to the array capacity |
| CVE-2026-97940 | 7.8 HIGH | ipv6: fix fib6 walker UAF on seq stop |
Showing top 20 of 372 CVEs. View all on vendor page → →
IV. Related Vulnerabilities
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Same vendor: Linux
-
CVE-2026-98384
bpf: Fix out-of-bounds read of sk_protocol in bpf_sock_destr -
CVE-2026-98383
bpf: Disallow bpf_skb_pull_data() for LWT_SEG6LOCAL -
CVE-2026-98382
bpf: Reject dev-bound-only programs on other devices -
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veth: manage XDP program pointers during channel resize -
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net/sched: reject IDR error pointers when deleting actions
V. Comments for CVE-2026-97992
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