CVE-2026-68202 (GCVE-0-2026-68202)

Vulnerability from cvelistv5 – Published: 2026-08-10 12:00 – Updated: 2026-08-19 16:31
VLAI
Title
ALSA: seq: close a re-opened queue timer in the destructor
Summary
In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: close a re-opened queue timer in the destructor queue_delete() closes the queue timer, then frees it. snd_seq_timer_close() clears q->timer->timeri. snd_use_lock_sync() then drains borrowers, and snd_seq_timer_delete() frees q->timer. A borrower can re-open the timer inside that window. A SET_QUEUE_CLIENT that took a queueptr() use_lock reference before the queue was unlinked runs snd_seq_timer_open() after the close. Open refuses re-open only while timeri is set, and the close just cleared it, so it re-opens timeri. snd_seq_timer_delete() does not close that instance. Its snd_seq_timer_stop() is a no-op, because running was cleared first. So it frees q->timer with the instance still live. The queue is freed next. The instance stays on the global timer with callback_data pointing at the freed queue. A non-owner START on the unlocked queue arms it. The next tick derefs the freed queue in snd_seq_timer_interrupt(). Reachable by an unprivileged user with access to /dev/snd/seq. No CAP and no queue ownership required. Close any lingering instance in the destructor. There, ->timeri can no longer change: the queue is unlinked and all use_lock borrowers have drained, so no snd_seq_queue_use() can re-open it. Close it before clearing q->timer. snd_timer_close() waits for any in-flight snd_seq_timer_interrupt() to finish, and that callback still reads q->timer (via snd_seq_check_queue()), so q->timer must stay valid until it drains.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 9d9be6fc30f384f92c4e1b8ed40bd9d4796b7833 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < fb40d03ed792a8a8bf77aa0ee15df57b0ff78b07 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 24f0cabf173539f048946c8fc221131dc221f277 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 6a10025c7fd09a7d2af37a3ae1da188569fce470 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 31a6163e301d832060f8236f1ed17cbc1ca198df (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 2c4dc0ed50b05cd847a4b34b8cebf0775f19aeb9 (git)
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Linux Linux Affected: 2.6.12
Unaffected: 0 , < 2.6.12 (semver)
Unaffected: 6.1.183 , ≤ 6.1.* (semver)
Unaffected: 6.6.148 , ≤ 6.6.* (semver)
Unaffected: 6.12.101 , ≤ 6.12.* (semver)
Unaffected: 6.18.42 , ≤ 6.18.* (semver)
Unaffected: 7.1.6 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: seq: close a re-opened queue timer in the destructor\n\nqueue_delete() closes the queue timer, then frees it. snd_seq_timer_close()\nclears q-\u003etimer-\u003etimeri. snd_use_lock_sync() then drains borrowers, and\nsnd_seq_timer_delete() frees q-\u003etimer.\n\nA borrower can re-open the timer inside that window. A SET_QUEUE_CLIENT\nthat took a queueptr() use_lock reference before the queue was unlinked\nruns snd_seq_timer_open() after the close. Open refuses re-open only while\ntimeri is set, and the close just cleared it, so it re-opens timeri.\n\nsnd_seq_timer_delete() does not close that instance. Its snd_seq_timer_stop()\nis a no-op, because running was cleared first. So it frees q-\u003etimer with the\ninstance still live. The queue is freed next.\n\nThe instance stays on the global timer with callback_data pointing at the\nfreed queue. A non-owner START on the unlocked queue arms it. The next tick\nderefs the freed queue in snd_seq_timer_interrupt().\n\nReachable by an unprivileged user with access to /dev/snd/seq. No CAP and\nno queue ownership required.\n\nClose any lingering instance in the destructor. There, -\u003etimeri can no\nlonger change: the queue is unlinked and all use_lock borrowers have\ndrained, so no snd_seq_queue_use() can re-open it. Close it before clearing\nq-\u003etimer. snd_timer_close() waits for any in-flight snd_seq_timer_interrupt()\nto finish, and that callback still reads q-\u003etimer (via snd_seq_check_queue()),\nso q-\u003etimer must stay valid until it drains."
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            "baseSeverity": "HIGH",
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      "title": "ALSA: seq: close a re-opened queue timer in the destructor",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-68202",
    "datePublished": "2026-08-10T12:00:21.279Z",
    "dateReserved": "2026-07-30T09:28:09.374Z",
    "dateUpdated": "2026-08-19T16:31:21.607Z",
    "state": "PUBLISHED"
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Its snd_seq_timer_stop()\\nis a no-op, because running was cleared first. So it frees q-\u003etimer with the\\ninstance still live. The queue is freed next.\\n\\nThe instance stays on the global timer with callback_data pointing at the\\nfreed queue. A non-owner START on the unlocked queue arms it. The next tick\\nderefs the freed queue in snd_seq_timer_interrupt().\\n\\nReachable by an unprivileged user with access to /dev/snd/seq. No CAP and\\nno queue ownership required.\\n\\nClose any lingering instance in the destructor. There, -\u003etimeri can no\\nlonger change: the queue is unlinked and all use_lock borrowers have\\ndrained, so no snd_seq_queue_use() can re-open it. Close it before clearing\\nq-\u003etimer. snd_timer_close() waits for any in-flight snd_seq_timer_interrupt()\\nto finish, and that callback still reads q-\u003etimer (via snd_seq_check_queue()),\\nso q-\u003etimer must stay valid until it drains.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"sound/core/seq/seq_timer.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\"lessThan\":\"9d9be6fc30f384f92c4e1b8ed40bd9d4796b7833\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\"lessThan\":\"fb40d03ed792a8a8bf77aa0ee15df57b0ff78b07\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\"lessThan\":\"24f0cabf173539f048946c8fc221131dc221f277\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\"lessThan\":\"6a10025c7fd09a7d2af37a3ae1da188569fce470\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\"lessThan\":\"31a6163e301d832060f8236f1ed17cbc1ca198df\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\"lessThan\":\"2c4dc0ed50b05cd847a4b34b8cebf0775f19aeb9\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"sound/core/seq/seq_timer.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"2.6.12\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"2.6.12\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.1.183\",\"lessThanOrEqual\":\"6.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.148\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.101\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.42\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.6\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":7.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/24f0cabf173539f048946c8fc221131dc221f277\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/2c4dc0ed50b05cd847a4b34b8cebf0775f19aeb9\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/31a6163e301d832060f8236f1ed17cbc1ca198df\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/6a10025c7fd09a7d2af37a3ae1da188569fce470\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/9d9be6fc30f384f92c4e1b8ed40bd9d4796b7833\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/fb40d03ed792a8a8bf77aa0ee15df57b0ff78b07\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Important",
      "current_release_date": "2026-08-13T23:07:16+00:00",
      "cve": "CVE-2026-68202",
      "id": "CVE-2026-68202",
      "initial_release_date": "2026-08-10T00:00:00+00:00",
      "product_status:known_affected": "261",
      "product_status:known_not_affected": "1",
      "product_status:under_investigation": "14",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: ALSA: seq: close a re-opened queue timer in the destructor",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-68202.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2026-08-14T23:45:39Z",
      "cve": "CVE-2026-68202",
      "id": "CVE-2026-68202",
      "initial_release_date": "2026-08-14T23:45:39Z",
      "product_status:known_affected": "99",
      "product_status:known_not_affected": "197",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-68202",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-68202.json",
      "version": "2"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.