GHSA-c898-7qpg-fw83 · 深刻度： medium — In the Linux kernel, the following vulnerability has been resolved: bpf: Fix race in cpumap on...
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) <-- CFS preempts Task A --> 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 */ <-- Task A resumes --> __list_del_clearprev(flush_node) flush_node.prev->next = ... /* prev is NULL -> kernel oops */ Fix this by adding a local_lock_t to xdp_bulk_queue and acquiring it in bq_enqueue() and __cpu_map_flush(). These paths already run under local_bh_disable(), so use local_lock_nested_bh() which on non-RT is a pure annotation with no overhead, and on PREEMPT_RT provides a per-CPU sleeping lock that serializes access to the bq. To reproduce, insert an mdelay(100) between bq->count = 0 and __list_del_clearprev() in bq_flush_to_queue(), then run reproducer provided by syzkaller.
総合評価: CVE-2026-23342 は低リスク（19/100）。CVSS 深刻度は中。悪用される可能性が高い（EPSS 0.09%、1 パーセンタイル） 推奨対応: 総合リスクは低く緊急対応は不要です。通常の保守サイクルでパッチを適用し、CVSS / EPSS が上昇したら優先度を見直してください。
リスクは変動します。再評価に基づき、本ページの表示内容を更新しています。
EPSS は日次で悪用されやすさの相対度合いを推定します。パーセンタイルは採点済み CVE の中での相対位置（高いほど相対的に深刻）を示します。
| # | 日付 | 旧 EPSS スコア | 新 EPSS スコア | Δ（新 − 旧） |
|---|---|---|---|---|
| 1 | 2026-06-15 | 0.02% | 0.09% | +0.07% |
| 2 | 2026-03-25 | — | 0.02% | — |
EPSS の全履歴 （全 2 件）
この CVE の CVSS 指標。
| ベーススコア | バージョン | 深刻度 | ベクトル | 悪用しやすさ | 影響 | スコアの出典 |
|---|---|---|---|---|---|---|
| 4.7 | 3.1 | MEDIUM |
|
1.0 | 3.6 | [email protected] |
GHSA-c898-7qpg-fw83 · 深刻度： medium — In the Linux kernel, the following vulnerability has been resolved: bpf: Fix race in cpumap on...
| vendor | priority | summary | link |
|---|---|---|---|
debian
|
unimportant | CVE-2026-23342 unimportant priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. | https://security-tracker.debian.org/tracker/CVE-2026-23342 |
redhat
|
— | — | https://access.redhat.com/security/cve/CVE-2026-23342 |
suse
|
medium | CVE-2026-23342 severity moderate: SUSE including 26 source package names (cluster-md-kmp-default, dlm-kmp-default, …), 226 product×package rows across 40 product lines (SUSE Linux Enterprise High Availability Extension 15 SP7, SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS, … (40 product lines)): Known Not Affected 226. | https://www.suse.com/security/cve/CVE-2026-23342/ |
ubuntu
|
medium | CVE-2026-23342 medium priority: Ubuntu including 157 source packages (linux, linux-allwinner-5.19, …), 1256 status rows across 8 suites (bionic, focal, jammy, noble, questing, trusty, upstream, xenial): DNE 871, ignored 166, not-affected 136, released 83. | https://ubuntu.com/security/CVE-2026-23342 |
| ベンダー | 製品 | バージョン | 生の CPE |
|---|---|---|---|
| linux | linux_kernel | >= 6.18.1, < 6.18.17 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | >= 6.19, < 6.19.7 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | 6.18 | cpe:2.3:o:linux:linux_kernel:6.18:-:*:*:*:*:*:* |
| linux | linux_kernel | 7.0 | cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:* |
| linux | linux_kernel | 7.0 | cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:* |
| linux | linux_kernel | 7.0 | cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:* |
| linux | linux_kernel | 7.0 | cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:* |
| linux | linux_kernel | 7.0 | cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:* |
| linux | linux_kernel | 7.0 | cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:* |
| linux | linux_kernel | 7.0 | cpe:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:* |