{"id":"CVE-2026-53193","title":"ALSA: timer: Forcibly close timer instances at closing","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: timer: Forcibly close timer instances at closing\n\nWhen snd_timer object is freed via snd_timer_free() and still pending\nsnd_timer_instance objects are assigned to…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= 37745918e0e7575bc40f38da93a99b9fa6406224 < 586b219a22b1032b28b8bd356b963276c5e5bf53","Linux >= 37745918e0e7575bc40f38da93a99b9fa6406224 < f46093dd22969037beb1fce2e043f3236be41c92","Linux >= 37745918e0e7575bc40f38da93a99b9fa6406224 < 60e73ab87b84bbd6bd7ddd1d16019a3a3705ab8f","Linux >= 37745918e0e7575bc40f38da93a99b9fa6406224 < da3039e91d1f835874ed6e9a33ea19ee80c2cb92","Linux 6.12"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-16T15:26:37.858700Z"},"published":"2026-06-25","updated":"2026-10-16","sourceUpdated":"2026-10-16T15:31:39.378Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-53193","references":[{"url":"https://git.kernel.org/stable/c/586b219a22b1032b28b8bd356b963276c5e5bf53"},{"url":"https://git.kernel.org/stable/c/f46093dd22969037beb1fce2e043f3236be41c92"},{"url":"https://git.kernel.org/stable/c/60e73ab87b84bbd6bd7ddd1d16019a3a3705ab8f"},{"url":"https://git.kernel.org/stable/c/da3039e91d1f835874ed6e9a33ea19ee80c2cb92"}],"tags":["cve.org"],"epss":0.00141,"epssPercentile":0.03062,"ingestedAt":"2026-10-16T17:24:46.735Z","slug":"CVE-2026-53193","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nALSA: timer: Forcibly close timer instances at closing\n\nWhen snd_timer object is freed via snd_timer_free() and still pending\nsnd_timer_instance objects are assigned to the timer object, it tries\nto unlink all instances and just set NULL to each ti->timer, then\nreleases the resources immediately.  The problem is, however, when\nthere are slave timer instances that are associated with a master\ninstance linked to this timer: namely, those slave instances still\npoint to the freed timer object although the master instance is\nunlinked, which may lead to user-after-free.  The bug can be easily\ntriggered particularly when a new userspace-driven timers\n(CONFIG_SND_UTIMER) is involved, since it can create and delete the\ntimer object via a simple file open/close, while the other\napplications may keep accessing to that timer.\n\nThis patch is an attempt to paper over the problem above: now instead\nof just unlinking, call snd_timer_close[_locked]() forcibly for each\npending timer instance, so that all assigned slave timer instances are\nproperly detached, too.  Since snd_timer_close() might be called later\nby the driver that created that instance, the check of\nSNDRV_TIMER_IFLG_DEAD is added at the beginning, too.\n\n## Affected\n\n- `Linux >= 37745918e0e7575bc40f38da93a99b9fa6406224 < 586b219a22b1032b28b8bd356b963276c5e5bf53`\n- `Linux >= 37745918e0e7575bc40f38da93a99b9fa6406224 < f46093dd22969037beb1fce2e043f3236be41c92`\n- `Linux >= 37745918e0e7575bc40f38da93a99b9fa6406224 < 60e73ab87b84bbd6bd7ddd1d16019a3a3705ab8f`\n- `Linux >= 37745918e0e7575bc40f38da93a99b9fa6406224 < da3039e91d1f835874ed6e9a33ea19ee80c2cb92`\n- `Linux 6.12`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}