CVE-2026-23342
published 2026-03-25CVE-2026-23342: In the Linux kernel, the following vulnerability has been resolved: bpf: Fix race in cpumap on PREEMPT_RT On PREEMPT_RT kernels, the per-CPU xdp_bulk_queue…
PriorityP417medium4.7CVSS 3.1
AVLACHPRLUINSUCNINAH
EPSS
0.09%
0.5th percentile
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix race in cpumap on PREEMPT_RT
On PREEMPT_RT kernels, the per-CPU xdp_bulk_queue (bq) can be accessed
concurrently by multiple preemptible tasks on the same CPU.
The original code assumes bq_enqueue() and __cpu_map_flush() run
atomically with respect to each other on the same CPU, relying on
local_bh_disable() to prevent preemption. However, on PREEMPT_RT,
local_bh_disable() only calls migrate_disable() (when
PREEMPT_RT_NEEDS_BH_LOCK is not set) and does not disable
preemption, which allows CFS scheduling to preempt a task during
bq_flush_to_queue(), enabling another task on the same CPU to enter
bq_enqueue() and operate on the same per-CPU bq concurrently.
This leads to several races:
1. Double __list_del_clearprev(): after bq->count is reset in
bq_flush_to_queue(), a preempting task can call bq_enqueue() ->
bq_flush_to_queue() on the same bq when bq->count reaches
CPU_MAP_BULK_SIZE. Both tasks then call __list_del_clearprev()
on the same bq->flush_node, the second call dereferences the
prev pointer that was already set to NULL by the first.
2. bq->count and bq->q[] races: concurrent bq_enqueue() can corrupt
the packet queue while bq_flush_to_queue() is processing it.
The race between task A (__cpu_map_flush -> bq_flush_to_queue) and
task B (bq_enqueue -> bq_flush_to_queue) on the same CPU:
Task A (xdp_do_flush) Task B (cpu_map_enqueue)
---------------------- ------------------------
bq_flush_to_queue(bq)
spin_lock(&q->producer_lock)
/* flush bq->q[] to ptr_ring */
bq->count = 0
spin_unlock(&q->producer_lock)
bq_enqueue(rcpu, xdpf)
bq->q[bq->count++] = xdpf
/* ... more enqueues until full ... */
bq_flush_to_queue(bq)
spin_lock(&q->producer_lock)
/* flush to ptr_ring */
spin_unlock(&q->producer_lock)
__list_del_clearprev(flush_node)
/* sets flush_node.prev = NULL */
__list_del_clearprev(flush_node)
flush_node.prev->next = ...
/* prev is NULL -> kernel oops */
Fix this by adding a lo
Affected
12 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | linux | < linux 6.19.8-1 (forky) | linux 6.19.8-1 (forky) |
| linux | linux | — | — |
| linux | linux | >= 3253cb49cbad4772389d6ef55be75db1f97da910 < 7466ae2aeed483de80c5d8dea0913cf74038b652 | 7466ae2aeed483de80c5d8dea0913cf74038b652 |
| linux | linux | >= 3253cb49cbad4772389d6ef55be75db1f97da910 < e67299e1044349ad0088d52c6bc5764cc1816c06 | e67299e1044349ad0088d52c6bc5764cc1816c06 |
| linux | linux | >= 3253cb49cbad4772389d6ef55be75db1f97da910 < 869c63d5975d55e97f6b168e885452b3da20ea47 | 869c63d5975d55e97f6b168e885452b3da20ea47 |
| linux | linux_kernel | — | — |
| linux | linux_kernel | — | — |
| linux | linux_kernel | >= 0 < 6.19.8-1 | 6.19.8-1 |
| linux | linux_kernel | >= 6.18.0 < 6.18.17 | 6.18.17 |
| linux | linux_kernel | >= 6.18.1 < 6.18.17 | 6.18.17 |
| linux | linux_kernel | >= 6.19 < 6.19.7 | 6.19.7 |
| linux | linux_kernel | >= 6.19.0 < 6.19.7 | 6.19.7 |
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GHSA
GHSA-c898-7qpg-fw83: In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix race in cpumap on PREEMPT_RT
On PREEMPT_RT kernels, the per-CPU xdp_bul
ghsa_unreviewed·2026-03-25
CVE-2026-23342 GHSA-c898-7qpg-fw83: In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix race in cpumap on PREEMPT_RT
On PREEMPT_RT kernels, the per-CPU xdp_bul
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix race in cpumap on PREEMPT_RT
On PREEMPT_RT kernels, the per-CPU xdp_bulk_queue (bq) can be accessed
concurrently by multiple preemptible tasks on the same CPU.
The original code assumes bq_enqueue() and __cpu_map_flush() run
atomically with respect to each other on the same CPU, relying on
local_bh_disable() to prevent preemption. However, on PREEMPT_RT,
local_bh_disable() only calls migrate_disable() (when
PREEMPT_RT_NEEDS_BH_LOCK is not set) and does not disable
preemption, which allows CFS scheduling to preempt a task during
bq_flush_to_queue(), enabling another task on the same CPU to enter
bq_enqueue() and operate on the same per-CPU bq concurrently.
This leads to several races:
1. Double __list_del_clea
OSV
CVE-2026-23342: In the Linux kernel, the following vulnerability has been resolved: bpf: Fix race in cpumap on PREEMPT_RT On PREEMPT_RT kernels, the per-CPU xdp_bulk_
osv·2026-03-25
CVE-2026-23342 CVE-2026-23342: In the Linux kernel, the following vulnerability has been resolved: bpf: Fix race in cpumap on PREEMPT_RT On PREEMPT_RT kernels, the per-CPU xdp_bulk_
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix race in cpumap on PREEMPT_RT On PREEMPT_RT kernels, the per-CPU xdp_bulk_queue (bq) can be accessed concurrently by multiple preemptible tasks on the same CPU. The original code assumes bq_enqueue() and __cpu_map_flush() run atomically with respect to each other on the same CPU, relying on local_bh_disable() to prevent preemption. However, on PREEMPT_RT, local_bh_disable() only calls migrate_disable() (when PREEMPT_RT_NEEDS_BH_LOCK is not set) and does not disable preemption, which allows CFS scheduling to preempt a task during bq_flush_to_queue(), enabling another task on the same CPU to enter bq_enqueue() and operate on the same per-CPU bq concurrently. This leads to several races: 1. Double __list_del_clearprev
OSV
bpf: Fix race in cpumap on PREEMPT_RT
osv·2026-03-25
CVE-2026-23342 bpf: Fix race in cpumap on PREEMPT_RT
bpf: Fix race in cpumap on PREEMPT_RT
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix race in cpumap on PREEMPT_RT
On PREEMPT_RT kernels, the per-CPU xdp_bulk_queue (bq) can be accessed
concurrently by multiple preemptible tasks on the same CPU.
The original code assumes bq_enqueue() and __cpu_map_flush() run
atomically with respect to each other on the same CPU, relying on
local_bh_disable() to prevent preemption. However, on PREEMPT_RT,
local_bh_disable() only calls migrate_disable() (when
PREEMPT_RT_NEEDS_BH_LOCK is not set) and does not disable
preemption, which allows CFS scheduling to preempt a task during
bq_flush_to_queue(), enabling another task on the same CPU to enter
bq_enqueue() and operate on the same per-CPU bq concurrently.
This leads to se
Red Hat
kernel: bpf: Fix race in cpumap on PREEMPT_RT
vendor_redhat·2026-03-25
CVE-2026-23342 CWE-367 kernel: bpf: Fix race in cpumap on PREEMPT_RT
kernel: bpf: Fix race in cpumap on PREEMPT_RT
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix race in cpumap on PREEMPT_RT
On PREEMPT_RT kernels, the per-CPU xdp_bulk_queue (bq) can be accessed
concurrently by multiple preemptible tasks on the same CPU.
The original code assumes bq_enqueue() and __cpu_map_flush() run
atomically with respect to each other on the same CPU, relying on
local_bh_disable() to prevent preemption. However, on PREEMPT_RT,
local_bh_disable() only calls migrate_disable() (when
PREEMPT_RT_NEEDS_BH_LOCK is not set) and does not disable
preemption, which allows CFS scheduling to preempt a task during
bq_flush_to_queue(), enabling another task on the same CPU to enter
bq_enqueue() and operate on the same per-CPU bq concurrently.
This leads t
Debian
CVE-2026-23342: linux - In the Linux kernel, the following vulnerability has been resolved: bpf: Fix ra...
vendor_debian·2026
CVE-2026-23342 [LOW] CVE-2026-23342: linux - In the Linux kernel, the following vulnerability has been resolved: bpf: Fix ra...
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix race in cpumap on PREEMPT_RT On PREEMPT_RT kernels, the per-CPU xdp_bulk_queue (bq) can be accessed concurrently by multiple preemptible tasks on the same CPU. The original code assumes bq_enqueue() and __cpu_map_flush() run atomically with respect to each other on the same CPU, relying on local_bh_disable() to prevent preemption. However, on PREEMPT_RT, local_bh_disable() only calls migrate_disable() (when PREEMPT_RT_NEEDS_BH_LOCK is not set) and does not disable preemption, which allows CFS scheduling to preempt a task during bq_flush_to_queue(), enabling another task on the same CPU to enter bq_enqueue() and operate on the same per-CPU bq concurrently. This leads to several races: 1. Double __list_del_clearprev
No detection rules found.
No public exploits indexed.
2026-03-25
Published