242 lines
14 KiB
JSON
242 lines
14 KiB
JSON
{
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"dataType": "CVE_RECORD",
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"dataVersion": "5.2",
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"cveMetadata": {
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"cveId": "CVE-2026-74503",
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"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"state": "PUBLISHED",
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"assignerShortName": "Linux",
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"dateReserved": "2026-08-15T05:44:03.908Z",
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"datePublished": "2026-08-15T12:27:28.208Z",
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"dateUpdated": "2026-10-16T19:05:50.728Z"
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},
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"containers": {
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"cna": {
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"providerMetadata": {
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"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"shortName": "Linux",
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"dateUpdated": "2026-08-17T05:47:54.696Z"
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},
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"descriptions": [
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{
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"lang": "en",
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: timer: Clear SNDRV_TIMER_IFLG_DEAD once the close completes\n\nsnd_timer_close_locked() marks an instance with SNDRV_TIMER_IFLG_DEAD\nand returns early when the flag is already set, but the flag is never\ncleared again. A completed close ends in remove_slave_links(), which\nleaves timeri->timer NULL, so a second close is already harmless through\nthe timer == NULL path; the early return can only be reached by an\ninstance that was opened again in between. For such an instance the\nclose unlinks nothing, so snd_timer_instance_free() frees an object that\nis still on timer->open_list_head, still on snd_timer_master_list if it\nwas opened with a slave key, still owns any adopted slaves, and still\nholds its timer and module references.\n\nsnd_seq_timer_open() reopens an instance exactly like that: it retries\nits fallback open on the same object after a failure that has already\nrun snd_timer_close_locked() internally. An unprivileged user with\naccess to /dev/snd/timer and /dev/snd/seq can force that failure, since\nsnd_timer_check_master() returns -EBUSY when a pending slave matches the\nnew master's (slave_class, slave_id) key and the target timer has\nreached max_instances, and SNDRV_TIMER_IOCTL_SELECT with dev_class =\nSNDRV_TIMER_CLASS_SLAVE keeps the caller-supplied dev_sclass, so a\nsequencer queue's key can be forged. The freed instance is afterwards\ndereferenced by any further snd_timer_open() on that timer, by\nsnd_timer_check_slave(), and by /proc/asound/timers, which faults on the\nstale ti->owner pointer.\n\nThe flag only has to be visible while the close is in progress, which is\nall its other users need. Clear it in remove_slave_links(), under the\nsame timer->lock that sets it, once the instance is off every list."
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}
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],
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"metrics": [
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{
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"cvssV3_1": {
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"version": "3.1",
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"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
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"baseScore": 7.8,
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"baseSeverity": "HIGH"
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},
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"scenarios": [
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{
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"lang": "en",
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"value": "AV:L - Exploitation requires local ioctl access to /dev/snd/timer and /dev/snd/seq to forge timer slave keys and drive snd_seq_timer_open() retry logic; there is no network, adjacent-wireless, or physical-device entry path.\nAC:L - The attacker fully controls the ioctl and sequencer queue sequence that forces the initial -EBUSY close, retries snd_timer_open() on the same instance, and later triggers free; no uncontrollable timing, memory layout, or rare kernel state is required beyond standard ALSA being enabled.\nPR:L - The fix commit and reachable ioctl paths require only an unprivileged local user with access to ALSA device nodes (/dev/snd/timer and /dev/snd/seq), typical on desktops, kiosks, and Android systems via the audio group or equivalent permissions, not real root in the init namespace.\nUI:N - Exploitation is self-contained through attacker-initiated timer SELECT ioctls and sequencer queue open/close operations; no victim interaction such as opening files, mounting filesystems, or clicking prompts is required.\nS:U - Impact is kernel memory corruption and potential local privilege escalation within the same kernel address space; it does not cross a VM, container, or IOMMU security boundary into a separate authority.\nC:H - A use-after-free of snd_timer_instance leaves dangling list pointers; freed memory can be reallocated and later dereferenced by snd_timer_open(), snd_timer_check_slave(), or /proc/asound/timers, enabling arbitrary kernel memory read primitives.\nI:H - The UAF frees a structure still linked on timer open/master lists while retaining timer and module references, allowing heap reuse and memory corruption that can be leveraged for arbitrary kernel writes or control-flow hijacking.\nA:H - Stale timer instance pointers are dereferenced during subsequent timer operations and /proc/asound/timers reads, causing kernel faults/oops; UAF reliably threatens crashes even before full exploitation."
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}
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]
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}
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],
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"affected": [
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{
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"product": "Linux",
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"vendor": "Linux",
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"defaultStatus": "unaffected",
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"programFiles": [
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"sound/core/timer.c"
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],
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"versions": [
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{
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"version": "586b219a22b1032b28b8bd356b963276c5e5bf53",
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"lessThan": "bb016091010ec401a06e6bdace0cd944ee03d371",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "f46093dd22969037beb1fce2e043f3236be41c92",
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"lessThan": "a26a2e52736f9e39843ca66a2e1ce6bf1adbcd1e",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "da3039e91d1f835874ed6e9a33ea19ee80c2cb92",
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"lessThan": "0c561fab50991df10b1e4daca25886c34a2a9c07",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "da3039e91d1f835874ed6e9a33ea19ee80c2cb92",
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"lessThan": "c2744d5f3aea474513fd2298daecb94a952ce441",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "60e73ab87b84bbd6bd7ddd1d16019a3a3705ab8f",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "6.12.94",
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"lessThan": "6.12.103",
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"status": "affected",
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"versionType": "semver"
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},
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{
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"version": "6.18.36",
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"lessThan": "6.18.44",
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"status": "affected",
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"versionType": "semver"
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},
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{
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"version": "7.0.13",
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"lessThan": "7.1",
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"status": "affected",
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"versionType": "semver"
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}
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]
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},
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{
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"product": "Linux",
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"vendor": "Linux",
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"defaultStatus": "affected",
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"programFiles": [
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"sound/core/timer.c"
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],
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"versions": [
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{
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"version": "7.1",
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"status": "affected"
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},
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{
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"version": "0",
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"lessThan": "7.1",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.12.103",
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"lessThanOrEqual": "6.12.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.18.44",
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"lessThanOrEqual": "6.18.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "7.1.8",
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"lessThanOrEqual": "7.1.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "7.2",
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"lessThanOrEqual": "*",
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"status": "unaffected",
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"versionType": "original_commit_for_fix"
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}
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]
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}
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],
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"cpeApplicability": [
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"nodes": [
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"operator": "OR",
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"negate": false,
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"cpeMatch": [
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "6.12.94",
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"versionEndExcluding": "6.12.103"
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},
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "6.18.36",
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"versionEndExcluding": "6.18.44"
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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]
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}
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],
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"references": [
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{
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"url": "https://git.kernel.org/stable/c/bb016091010ec401a06e6bdace0cd944ee03d371"
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},
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{
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"url": "https://git.kernel.org/stable/c/a26a2e52736f9e39843ca66a2e1ce6bf1adbcd1e"
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},
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{
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"url": "https://git.kernel.org/stable/c/0c561fab50991df10b1e4daca25886c34a2a9c07"
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},
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{
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"url": "https://git.kernel.org/stable/c/c2744d5f3aea474513fd2298daecb94a952ce441"
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}
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],
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"title": "ALSA: timer: Clear SNDRV_TIMER_IFLG_DEAD once the close completes",
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"x_generator": {
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"engine": "bippy-1.2.0"
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}
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"adp": [
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{
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"metrics": [
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{
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"other": {
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"type": "ssvc",
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"content": {
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"id": "CVE-2026-74503",
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"role": "CISA Coordinator",
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"options": [
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{
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"Exploitation": "none"
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},
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{
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"Automatable": "no"
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},
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{
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"Technical Impact": "total"
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}
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],
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"version": "2.0.3",
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"timestamp": "2026-10-16T18:58:23.278795Z"
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}
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}
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}
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],
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"title": "CISA ADP Vulnrichment",
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"providerMetadata": {
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"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
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"shortName": "CISA-ADP",
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"dateUpdated": "2026-10-16T19:05:50.728Z"
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}
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}
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]
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}
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} |