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CVE-2026-74594— sched/psi: Shut down rtpoll_timer in psi_cgroup_free()

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.

Linux kernel是美国Linux基金会开源的一个操作系统内核。 Linux kernel 5.14版本存在安全漏洞，该漏洞源于sched/psi组件中psi_schedule_rtpoll_work()与psi_trigger_destroy()存在竞争条件，可能导致释放后重用，定时器在已释放的内存上运行。

CVSS 7.8 · High EPSS 0.13% · P2

Possible ATT&CK Techniques 1 AI

T1068 · Exploitation for Privilege Escalation

Affected Version Matrix 23

VendorProduct Version RangeStatus
Linux Linux 6bfcb6178925b1fd28c102e53d403091b8f49396< 4addb102154b7cf6e2310ccbe20c3c08619e520d affected
8f91efd870ea5d8bc10b0fcc9740db51cd4c0c83< 894a9300d7fb2e2951da92e565ae6de7ddfb0a69 affected
8f91efd870ea5d8bc10b0fcc9740db51cd4c0c83< 1e5ca82eee59caca6988f9d6e859786aab8a5fa0 affected
8f91efd870ea5d8bc10b0fcc9740db51cd4c0c83< 310b5a537a78c358a4cd244bd767c1a517a05459 affected
8f91efd870ea5d8bc10b0fcc9740db51cd4c0c83< 806fcff98c1d7cb3c1dc0015e55ebdbe819e6b08 affected
8f91efd870ea5d8bc10b0fcc9740db51cd4c0c83< 8037c5b2b2a447df52542f4d8535895d837bdcbd affected
8f91efd870ea5d8bc10b0fcc9740db51cd4c0c83< 611e7821c4f83a671455658797336faecc3a5196 affected
8f91efd870ea5d8bc10b0fcc9740db51cd4c0c83< 5457025fa8ca3c0d2732109513de839e3e797190 affected
… +15 more rows
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I. Basic Information for CVE-2026-74594

Vulnerability Information
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Vulnerability Title
sched/psi: Shut down rtpoll_timer in psi_cgroup_free()
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: sched/psi: Shut down rtpoll_timer in psi_cgroup_free() psi_schedule_rtpoll_work() is called locklessly from the scheduler hotpath and can race psi_trigger_destroy() taking down the last rtpoll trigger under rtpoll_trigger_lock: psi_schedule_rtpoll_work() psi_trigger_destroy() rcu_read_lock(); task = rcu_dereference(rtpoll_task); rcu_assign_pointer(rtpoll_task, NULL); timer_delete(&rtpoll_timer); mod_timer(&rtpoll_timer, ...); rcu_read_unlock(); synchronize_rcu(); kthread_stop(task_to_destroy); The group can then be freed with the re-armed timer still pending, and poll_timer_fn() runs on freed memory. 461daba06bdc ("psi: eliminate kthread_worker from psi trigger scheduling mechanism") deleted the timer synchronously after the synchronize_rcu(), which prevented this but raced trigger creation instead: the deletion could cancel the timer that a new trigger set armed during the grace period and, as creation also reinitialized the timer at the time, corrupt it. 8f91efd870ea ("psi: Fix race between psi_trigger_create/destroy") moved the initialization into group_init() and the deletion into the locked section, trading the creation races for the window above. Neither placement in the destruction path works. A pending timer firing while the group is alive is harmless though. poll_timer_fn() just wakes the rtpoll waitqueue and doesn't re-arm itself. Bind the timer to the group's lifetime instead and shut it down in psi_cgroup_free(). Nothing can arm it by then. timer_shutdown_sync() because the timer is never armed again.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会开源的一个操作系统内核。 Linux kernel 5.14版本存在安全漏洞，该漏洞源于sched/psi组件中psi_schedule_rtpoll_work()与psi_trigger_destroy()存在竞争条件，可能导致释放后重用，定时器在已释放的内存上运行。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 6bfcb6178925b1fd28c102e53d403091b8f49396 ~ 4addb102154b7cf6e2310ccbe20c3c08619e520d -
Linux Linux 5.14 -

II. Public POCs for CVE-2026-74594

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III. Intelligence Information for CVE-2026-74594

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Patches & Fixes for CVE-2026-74594 (8)

Same Patch Batch · Linux · 2026-08-22 · 149 CVEs total

CVE-2026-74612 10.0 CRITICAL veth: fix skb length accounting after XDP frag adjustment
CVE-2026-74705 10.0 CRITICAL udp: fix potential use-after-free in tunnel segmentation
CVE-2026-74597 9.8 CRITICAL ip6_tunnel: clear skb2->cb[] in ip6ip6_err()
CVE-2026-74611 9.8 CRITICAL tls: rx: restore msg_iter before TLS 1.3 optimistic retry
CVE-2026-74608 9.8 CRITICAL smb: client: Fix use-after-free in cifs_try_adding_channels()
CVE-2026-74662 9.8 CRITICAL inet: frags: publish queues before arming timer
CVE-2026-74616 9.8 CRITICAL xdp: reject clones that overrun skb_shared_info tailroom
CVE-2026-74727 9.8 CRITICAL ovpn: skip rehash for peers already removed from by_id
CVE-2026-74617 9.8 CRITICAL dibs: initialise dibs->lock in dibs_dev_alloc()
CVE-2026-74688 9.8 CRITICAL sctp: clear control chunk transport if it is being removed
CVE-2026-74591 9.8 CRITICAL mm/filemap: __filemap_add_folio() restore index before retrying
CVE-2026-74628 9.8 CRITICAL net/x25: fix use-after-free of the socket by its timers
CVE-2026-74586 9.8 CRITICAL sctp: clear new_transport when removing a peer
CVE-2026-74587 9.8 CRITICAL sctp: fix use-after-free of cached ASCONF chunk
CVE-2026-74588 9.8 CRITICAL sctp: keep chunk->transport in step with the list it is queued on
CVE-2026-74669 9.8 CRITICAL ipvs: clear IPv4 options after rebasing tunnel ICMP errors
CVE-2026-74723 9.8 CRITICAL btrfs: lzo: reject inline extents without valid headers
CVE-2026-74730 9.8 CRITICAL NFS: Pin the 'struct nfs_server' during a FREE_STATEID call
CVE-2026-74712 9.3 CRITICAL vdpa/mlx5: Fix buffer length in create_direct_keys()
CVE-2026-74665 9.1 CRITICAL net: fix skb length accounting after generic XDP frag adjustment

Showing top 20 of 149 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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