GHSA-x7q8-xcw2-7mfg · 深刻度： high — In the Linux kernel, the following vulnerability has been resolved: mm: blk-cgroup: fix use...
In the Linux kernel, the following vulnerability has been resolved: mm: blk-cgroup: fix use-after-free in cgwb_release_workfn() cgwb_release_workfn() calls css_put(wb->blkcg_css) and then later accesses wb->blkcg_css again via blkcg_unpin_online(). If css_put() drops the last reference, the blkcg can be freed asynchronously (css_free_rwork_fn -> blkcg_css_free -> kfree) before blkcg_unpin_online() dereferences the pointer to access blkcg->online_pin, resulting in a use-after-free: BUG: KASAN: slab-use-after-free in blkcg_unpin_online (./include/linux/instrumented.h:112 ./include/linux/atomic/atomic-instrumented.h:400 ./include/linux/refcount.h:389 ./include/linux/refcount.h:432 ./include/linux/refcount.h:450 block/blk-cgroup.c:1367) Write of size 4 at addr ff11000117aa6160 by task kworker/71:1/531 Workqueue: cgwb_release cgwb_release_workfn Call Trace: <TASK> blkcg_unpin_online (./include/linux/instrumented.h:112 ./include/linux/atomic/atomic-instrumented.h:400 ./include/linux/refcount.h:389 ./include/linux/refcount.h:432 ./include/linux/refcount.h:450 block/blk-cgroup.c:1367) cgwb_release_workfn (mm/backing-dev.c:629) process_scheduled_works (kernel/workqueue.c:3278 kernel/workqueue.c:3385) Freed by task 1016: kfree (./include/linux/kasan.h:235 mm/slub.c:2689 mm/slub.c:6246 mm/slub.c:6561) css_free_rwork_fn (kernel/cgroup/cgroup.c:5542) process_scheduled_works (kernel/workqueue.c:3302 kernel/workqueue.c:3385) ** Stack based on commit 66672af7a095 ("Add linux-next specific files for 20260410") I am seeing this crash sporadically in Meta fleet across multiple kernel versions. A full reproducer is available at: https://github.com/leitao/debug/blob/main/reproducers/repro_blkcg_uaf.sh (The race window is narrow. To make it easily reproducible, inject a msleep(100) between css_put() and blkcg_unpin_online() in cgwb_release_workfn(). With that delay and a KASAN-enabled kernel, the reproducer triggers the splat reliably in less than a second.) Fix this by moving blkcg_unpin_online() before css_put(), so the cgwb's CSS reference keeps the blkcg alive while blkcg_unpin_online() accesses it.
総合評価: CVE-2026-31586 は低リスク（32.3/100）。CVSS 深刻度は高。悪用される可能性が高い（EPSS 0.13%、3 パーセンタイル） 推奨対応: 悪用情報と EPSS の推移を監視し、必要に応じて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% | 0.13% | +0.11% |
| 2 | 2026-04-25 | — | 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 |
|---|---|---|---|---|---|---|
| 7.8 | 3.1 | HIGH |
|
1.8 | 5.9 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
GHSA-x7q8-xcw2-7mfg · 深刻度： high — In the Linux kernel, the following vulnerability has been resolved: mm: blk-cgroup: fix use...
| vendor | priority | summary | link |
|---|---|---|---|
debian
|
not yet assigned | CVE-2026-31586 not yet assigned priority: Debian including 2 source packages (linux, linux-6.1), 6 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 6. | https://security-tracker.debian.org/tracker/CVE-2026-31586 |
redhat
|
high | — | https://access.redhat.com/security/cve/CVE-2026-31586 |
suse
|
high | CVE-2026-31586 severity important: SUSE including 4 source package names (kernel-default, kernel-default-base, kernel-default-devel, kernel-source), 4 product×package rows across 1 product lines (SUSE Linux Enterprise Server 11 SP4 LTSS EXTREME CORE): Known Not Affected 4. | https://www.suse.com/security/cve/CVE-2026-31586/ |
ubuntu
|
medium | CVE-2026-31586 medium priority: Ubuntu including 161 source packages (linux, linux-allwinner-5.19, …), 1449 status rows across 9 suites (bionic, focal, jammy, noble, questing, resolute, trusty, upstream, xenial): DNE 1048, ignored 169, needed 121, released 83, not-affected 23, needs-triage 4, pending 1. | https://ubuntu.com/security/CVE-2026-31586 |
| ベンダー | 製品 | バージョン | 生の CPE |
|---|---|---|---|
| linux | linux_kernel | >= 4.19, < 6.6.136 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | >= 6.7, < 6.12.83 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | >= 6.13, < 6.18.24 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | >= 6.19, < 6.19.14 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | >= 7.0, < 7.0.1 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |