GHSA-vq3g-6qwh-5wj2 · 深刻度： unknown — In the Linux kernel, the following vulnerability has been resolved: net/sched: act_api: use RCU...
In the Linux kernel, the following vulnerability has been resolved: net/sched: act_api: use RCU with deferred freeing for action lifecycle When NEWTFILTER and DELFILTER are run concurrently it is possible to create a race with an associated action. Let's illustrate with CPU0 running NEWTFILTER and CPU1 running DELFILTER: 0: mutex_lock() <-- holds the idr lock 0: rcu_read_lock() 0: p = idr_find(idr, index) <-- action p is valid (RCU protects IDR) 0: mutex_unlock() <-- releases the idr lock 1: refcount_dec_and_mutex_lock() <-- refcnt 1->0, mutex held 1: idr_remove(idr, index) <-- Action removed from IDR 1: mutex_unlock() <-- mutex released allowing us to delete the action 1: tcf_action_cleanup(p); kfree(p) <-- Kfrees p immediately, no deferral 0: refcount_inc_not_zero(&p->tcfa_refcnt) <-- ouch, UAF p points to freed memory This patch fixes the race condition between NEWTFILTER and DELFILTER by adding struct rcu_head to tc_action used in the deferral and introducing a call_rcu() in the delete path to defer the final kfree(). Note: this is a revert of commit d7fb60b9cafb ("net_sched: get rid of tcfa_rcu") but also modernization/simplification to directly use kfree_rcu(). Let's illustrate the new restored code path: 0: rcu_read_lock() 1: refcount_dec_and_mutex_lock() <-- refcnt 1->0, mutex held 1: idr_remove(idr, index) 1: mutex_unlock() 1: call_rcu(&p->tcfa_rcu, tcf_action_rcu_free) <-- defer kfree after grace period 0: p = idr_find(idr, index) 0: refcount_inc_not_zero(&p->tcfa_refcnt) <-- fails, refcnt already 0 1: rcu_read_unlock() <-- release so freeing can run after grace period After CPU1 calls idr_remove(), the object is no longer reachable through the IDR. CPU0's subsequent idr_find() will return NULL, and even if it still held a stale pointer, the immediate kfree() is now deferred until after the RCU grace period, so no UAF can occur.
総合評価: CVE-2026-53264 は低リスク（6.8/100）。悪用される可能性が高い（EPSS 0.17%、7 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 | 2026-06-25 | — | 0.17% | — |
EPSS の全履歴 （全 1 件）
この CVE の CVSS 指標。
この CVE のデータセットに CVSS はありません。
GHSA-vq3g-6qwh-5wj2 · 深刻度： unknown — In the Linux kernel, the following vulnerability has been resolved: net/sched: act_api: use RCU...
| vendor | priority | summary | link |
|---|---|---|---|
debian
|
not yet assigned | CVE-2026-53264 not yet assigned priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 3, resolved 2. | https://security-tracker.debian.org/tracker/CVE-2026-53264 |
redhat
|
medium | — | https://access.redhat.com/security/cve/CVE-2026-53264 |
| ベンダー | 製品 | バージョン | 生の CPE |
|---|---|---|---|
| linux | linux_kernel | >= 4.14, < 5.10.259 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | >= 4.14, < 5.15.210 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | >= 4.14, < 6.1.176 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | >= 4.14, < 6.6.143 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | >= 4.14, < 6.12.94 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | >= 4.14, < 6.18.36 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | >= 4.14, < 7.0.13 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | >= 4.14, < 7.1 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |