ALSA: timer: Clear SNDRV_TIMER_IFLG_DEAD once the close completes
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_tim
CVE-2026-74503
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-74503
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "586b219a22b1032b28b8bd356b963276c5e5bf53",
"lessThan": "bb016091010ec401a06e6bdace0cd944ee03d371",
"versionType": "git"
},
{
"status": "affected",
"version": "f46093dd22969037beb1fce2e043f3236be41c92",
"lessThan": "a26a2e52736f9e39843ca66a2e1ce6bf1adbcd1e",
"versionType": "git"
},
{
"status": "affected",
"version": "da3039e91d1f835874ed6e9a33ea19ee80c2cb92",
"lessThan": "0c561fab50991df10b1e4daca25886c34a2a9c07",
"versionType": "git"
},
{
"status": "affected",
"version": "da3039e91d1f835874ed6e9a33ea19ee80c2cb92",
"lessThan": "c2744d5f3aea474513fd2298daecb94a952ce441",
"versionType": "git"
},
{
"status": "affected",
"version": "60e73ab87b84bbd6bd7ddd1d16019a3a3705ab8f",
"versionType": "git"
},
{
"status": "affected",
"version": "6.12.94",
"lessThan": "6.12.103",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.18.36",
"lessThan": "6.18.44",
"versionType": "semver"
},
{
"status": "affected",
"version": "7.0.13",
"lessThan": "7.1",
"versionType": "semver"
}
],
"programFiles": [
"sound/core/timer.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "7.1"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "7.1",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.12.103",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.44",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.8",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"sound/core/timer.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-74503
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #33183 · Revision 1
- Added to Heist Feed
- Publisher date