{"api_version":"1","generated_at":"2026-08-13T21:50:31+00:00","cve":"CVE-2026-68200","urls":{"html":"https://cve.report/CVE-2026-68200","api":"https://cve.report/api/cve/CVE-2026-68200.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-68200","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-68200"},"summary":{"title":"ALSA: timer: don't re-enter an instance callback that is still running","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: timer: don't re-enter an instance callback that is still running\n\nThe userspace-driven timer (utimer) TRIGGER ioctl calls\nsnd_timer_interrupt() directly with no serialization, so two threads\ntriggering the same utimer can run snd_timer_interrupt() on one\nsnd_timer concurrently.\n\nsnd_timer_process_callbacks() drops timer->lock around each instance\ncallback and marks the in-flight callback with the single\nSNDRV_TIMER_IFLG_CALLBACK bit; snd_timer_close_locked() waits on that\nbit to drain an in-flight callback before freeing the instance. The bit\ncannot represent two concurrent callbacks: when a second interrupt\nre-queues an instance whose callback is still running, both run at once,\nthe first to finish clears the bit, and the close-path drain then frees\nthe instance (and its callback_data) while the other callback is still\nlive - a use-after-free reachable by any user able to open\n/dev/snd/timer, both via a user timer instance and via a sequencer queue\ntimer bound to the utimer.\n\nsnd_timer_interrupt() sets IFLG_CALLBACK before dropping timer->lock, so\na concurrent interrupt already observes it under the lock. Skip\nre-queuing an instance (and its slaves) to the ack/sack list while its\ncallback is in flight; the accumulated pticks are delivered on the next\ntick, so no event is lost.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-10 13:20:07","updated_at":"2026-08-10 13:20:07"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/c1078130a4cd7e738f4b73afe99b3e68cbfbf884","name":"https://git.kernel.org/stable/c/c1078130a4cd7e738f4b73afe99b3e68cbfbf884","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/70d28bfcd6224eed75986b3b987b997e59643fa4","name":"https://git.kernel.org/stable/c/70d28bfcd6224eed75986b3b987b997e59643fa4","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/1395327a96614885552bae5fbb650e6dd182d49b","name":"https://git.kernel.org/stable/c/1395327a96614885552bae5fbb650e6dd182d49b","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/996c24377eea4d4506b7c3ccbbf1e490440b5e0b","name":"https://git.kernel.org/stable/c/996c24377eea4d4506b7c3ccbbf1e490440b5e0b","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-68200","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-68200","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 37745918e0e7575bc40f38da93a99b9fa6406224 996c24377eea4d4506b7c3ccbbf1e490440b5e0b git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 37745918e0e7575bc40f38da93a99b9fa6406224 1395327a96614885552bae5fbb650e6dd182d49b git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 37745918e0e7575bc40f38da93a99b9fa6406224 c1078130a4cd7e738f4b73afe99b3e68cbfbf884 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 37745918e0e7575bc40f38da93a99b9fa6406224 70d28bfcd6224eed75986b3b987b997e59643fa4 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.12","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.101 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.42 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.6 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2-rc5 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["sound/core/timer.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"996c24377eea4d4506b7c3ccbbf1e490440b5e0b","status":"affected","version":"37745918e0e7575bc40f38da93a99b9fa6406224","versionType":"git"},{"lessThan":"1395327a96614885552bae5fbb650e6dd182d49b","status":"affected","version":"37745918e0e7575bc40f38da93a99b9fa6406224","versionType":"git"},{"lessThan":"c1078130a4cd7e738f4b73afe99b3e68cbfbf884","status":"affected","version":"37745918e0e7575bc40f38da93a99b9fa6406224","versionType":"git"},{"lessThan":"70d28bfcd6224eed75986b3b987b997e59643fa4","status":"affected","version":"37745918e0e7575bc40f38da93a99b9fa6406224","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["sound/core/timer.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.12"},{"lessThan":"6.12","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.101","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.42","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.6","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2-rc5","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.101","versionStartIncluding":"6.12","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.42","versionStartIncluding":"6.12","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.6","versionStartIncluding":"6.12","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2-rc5","versionStartIncluding":"6.12","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: timer: don't re-enter an instance callback that is still running\n\nThe userspace-driven timer (utimer) TRIGGER ioctl calls\nsnd_timer_interrupt() directly with no serialization, so two threads\ntriggering the same utimer can run snd_timer_interrupt() on one\nsnd_timer concurrently.\n\nsnd_timer_process_callbacks() drops timer->lock around each instance\ncallback and marks the in-flight callback with the single\nSNDRV_TIMER_IFLG_CALLBACK bit; snd_timer_close_locked() waits on that\nbit to drain an in-flight callback before freeing the instance. The bit\ncannot represent two concurrent callbacks: when a second interrupt\nre-queues an instance whose callback is still running, both run at once,\nthe first to finish clears the bit, and the close-path drain then frees\nthe instance (and its callback_data) while the other callback is still\nlive - a use-after-free reachable by any user able to open\n/dev/snd/timer, both via a user timer instance and via a sequencer queue\ntimer bound to the utimer.\n\nsnd_timer_interrupt() sets IFLG_CALLBACK before dropping timer->lock, so\na concurrent interrupt already observes it under the lock. Skip\nre-queuing an instance (and its slaves) to the ack/sack list while its\ncallback is in flight; the accumulated pticks are delivered on the next\ntick, so no event is lost."}],"providerMetadata":{"dateUpdated":"2026-08-10T12:00:19.253Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/996c24377eea4d4506b7c3ccbbf1e490440b5e0b"},{"url":"https://git.kernel.org/stable/c/1395327a96614885552bae5fbb650e6dd182d49b"},{"url":"https://git.kernel.org/stable/c/c1078130a4cd7e738f4b73afe99b3e68cbfbf884"},{"url":"https://git.kernel.org/stable/c/70d28bfcd6224eed75986b3b987b997e59643fa4"}],"title":"ALSA: timer: don't re-enter an instance callback that is still running","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-68200","datePublished":"2026-08-10T12:00:19.253Z","dateReserved":"2026-07-30T09:28:09.374Z","dateUpdated":"2026-08-10T12:00:19.253Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-10 13:20:07","lastModifiedDate":"2026-08-10 13:20:07","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"68200","Ordinal":"1","Title":"ALSA: timer: don't re-enter an instance callback that is still r","CVE":"CVE-2026-68200","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"68200","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: timer: don't re-enter an instance callback that is still running\n\nThe userspace-driven timer (utimer) TRIGGER ioctl calls\nsnd_timer_interrupt() directly with no serialization, so two threads\ntriggering the same utimer can run snd_timer_interrupt() on one\nsnd_timer concurrently.\n\nsnd_timer_process_callbacks() drops timer->lock around each instance\ncallback and marks the in-flight callback with the single\nSNDRV_TIMER_IFLG_CALLBACK bit; snd_timer_close_locked() waits on that\nbit to drain an in-flight callback before freeing the instance. The bit\ncannot represent two concurrent callbacks: when a second interrupt\nre-queues an instance whose callback is still running, both run at once,\nthe first to finish clears the bit, and the close-path drain then frees\nthe instance (and its callback_data) while the other callback is still\nlive - a use-after-free reachable by any user able to open\n/dev/snd/timer, both via a user timer instance and via a sequencer queue\ntimer bound to the utimer.\n\nsnd_timer_interrupt() sets IFLG_CALLBACK before dropping timer->lock, so\na concurrent interrupt already observes it under the lock. Skip\nre-queuing an instance (and its slaves) to the ack/sack list while its\ncallback is in flight; the accumulated pticks are delivered on the next\ntick, so no event is lost.","Type":"Description","Title":"ALSA: timer: don't re-enter an instance callback that is still r"}]}}}