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CVE-2026-74503— ALSA: timer: Clear SNDRV_TIMER_IFLG_DEAD once the close completes

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 7.1版本存在安全漏洞，该漏洞源于ALSA timer子系统中关闭完成后未清除SNDRV_TIMER_IFLG_DEAD标志，可能导致释放后重用和空指针解引用。

CVSS 7.8 · High EPSS 0.13% · P3

Possible ATT&CK Techniques 1 AI

T1203 · Exploitation for Client Execution

Affected Version Matrix 14

VendorProduct Version RangeStatus
Linux Linux 586b219a22b1032b28b8bd356b963276c5e5bf53< bb016091010ec401a06e6bdace0cd944ee03d371 affected
f46093dd22969037beb1fce2e043f3236be41c92< a26a2e52736f9e39843ca66a2e1ce6bf1adbcd1e affected
da3039e91d1f835874ed6e9a33ea19ee80c2cb92< 0c561fab50991df10b1e4daca25886c34a2a9c07 affected
da3039e91d1f835874ed6e9a33ea19ee80c2cb92< c2744d5f3aea474513fd2298daecb94a952ce441 affected
60e73ab87b84bbd6bd7ddd1d16019a3a3705ab8f affected
6.12.94< 6.12.103 affected
6.18.36< 6.18.44 affected
7.0.13< 7.1 affected
… +6 more rows
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I. Basic Information for CVE-2026-74503

Vulnerability Information
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Vulnerability Title
ALSA: timer: Clear SNDRV_TIMER_IFLG_DEAD once the close completes
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: ALSA: timer: Clear SNDRV_TIMER_IFLG_DEAD once the close completes snd_timer_close_locked() marks an instance with SNDRV_TIMER_IFLG_DEAD and returns early when the flag is already set, but the flag is never cleared again. A completed close ends in remove_slave_links(), which leaves timeri->timer NULL, so a second close is already harmless through the timer == NULL path; the early return can only be reached by an instance that was opened again in between. For such an instance the close unlinks nothing, so snd_timer_instance_free() frees an object that is still on timer->open_list_head, still on snd_timer_master_list if it was opened with a slave key, still owns any adopted slaves, and still holds its timer and module references. snd_seq_timer_open() reopens an instance exactly like that: it retries its fallback open on the same object after a failure that has already run snd_timer_close_locked() internally. An unprivileged user with access to /dev/snd/timer and /dev/snd/seq can force that failure, since snd_timer_check_master() returns -EBUSY when a pending slave matches the new master's (slave_class, slave_id) key and the target timer has reached max_instances, and SNDRV_TIMER_IOCTL_SELECT with dev_class = SNDRV_TIMER_CLASS_SLAVE keeps the caller-supplied dev_sclass, so a sequencer queue's key can be forged. The freed instance is afterwards dereferenced by any further snd_timer_open() on that timer, by snd_timer_check_slave(), and by /proc/asound/timers, which faults on the stale ti->owner pointer. The flag only has to be visible while the close is in progress, which is all its other users need. Clear it in remove_slave_links(), under the same timer->lock that sets it, once the instance is off every list.
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 7.1版本存在安全漏洞，该漏洞源于ALSA timer子系统中关闭完成后未清除SNDRV_TIMER_IFLG_DEAD标志，可能导致释放后重用和空指针解引用。
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 586b219a22b1032b28b8bd356b963276c5e5bf53 ~ bb016091010ec401a06e6bdace0cd944ee03d371 -
Linux Linux 7.1 -

II. Public POCs for CVE-2026-74503

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III. Intelligence Information for CVE-2026-74503

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Patches & Fixes for CVE-2026-74503 (3)

Same Patch Batch · Linux · 2026-08-15 · 845 CVEs total

CVE-2026-74280 10.0 CRITICAL crypto: marvell/octeontx - fix DMA cleanup using wrong loop index
CVE-2026-74475 10.0 CRITICAL vxlan: use neigh_ha_snapshot() in route_shortcircuit()
CVE-2026-72407 10.0 CRITICAL geneve: validate inner network offset in geneve_gro_complete()
CVE-2026-74309 10.0 CRITICAL vdpa/octeon_ep: fix IRQ-to-ring mapping in interrupt handler
CVE-2026-72408 10.0 CRITICAL geneve: gate GRO hint in geneve_gro_complete() on gs->gro_hint
CVE-2026-72421 10.0 CRITICAL ipv4: fib: Don't ignore error route in local/main tables.
CVE-2026-74279 10.0 CRITICAL crypto: cavium/cpt - fix DMA cleanup using wrong loop index
CVE-2026-72493 9.9 CRITICAL net: serialize netif_running() check in enqueue_to_backlog()
CVE-2026-72084 9.8 CRITICAL scsi: target: Bound PR-OUT TransportID parsing to the received buffer
CVE-2026-72249 9.8 CRITICAL netfilter: flowtable: use dst in this direction when pushing IPIP header
CVE-2026-72248 9.8 CRITICAL netfilter: flowtable: support IPIP tunnel with direct xmit
CVE-2026-72494 9.8 CRITICAL RDMA/irdma: Replace waitqueue and flag with completion
CVE-2026-72220 9.8 CRITICAL sunrpc: harden rq_procinfo lifecycle to prevent double-free
CVE-2026-74345 9.8 CRITICAL RDMA/siw: Fix endpoint/socket association handling
CVE-2026-74255 9.8 CRITICAL tipc: fix UAF in tipc_l2_send_msg()
CVE-2026-72221 9.8 CRITICAL sunrpc: wait for in-flight TLS handshake callback when cancel loses race
CVE-2026-72226 9.8 CRITICAL batman-adv: tt: prevent TVLV OOB check overflow
CVE-2026-74428 9.8 CRITICAL rxrpc: Fix double unlock in rxrpc_recvmsg()
CVE-2026-72083 9.8 CRITICAL scsi: target: core: Fix iSCSI ISID use-after-free in REGISTER AND MOVE
CVE-2026-72234 9.8 CRITICAL batman-adv: access unicast_ttvn skb->data only after skb realloc

Showing top 20 of 845 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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