{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-53193", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-06-09T07:44:35.390Z", "datePublished": "2026-06-25T08:39:04.346Z", "dateUpdated": "2026-08-05T12:33:59.686Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:33:59.686Z" }, "descriptions": [ { "lang": "en", "value": "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 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." } ], "metrics": [ { "cvssV3_1": { "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" }, "scenarios": [ { "lang": "en", "value": "AV:L - The vulnerable path is reached through local `/dev/snd/timer` opens and ALSA timer ioctls, including `SNDRV_TIMER_IOCTL_CREATE`, `SELECT`, and later access to retained timer instances.\nAC:L - The attacker can create the userspace-driven timer, bind matching master/slave timer instances, close the timer fd to free the object, and then access the stale slave instance without relying on uncontrollable conditions.\nPR:L - The code path has no capability checks, but it requires a local user able to open `/dev/snd/timer` and issue ioctls.\nUI:N - No victim action is required after the attacker has local access; the attacker controls all needed file descriptors and ioctls.\nS:U - The impact is within the kernel/local system security authority and does not cross a VM, IOMMU, or other separate security boundary.\nC:H - This is a kernel use-after-free of `struct snd_timer`; stale timer pointers can be dereferenced by later ioctls and may expose reclaimed kernel heap contents or enable broader memory disclosure.\nI:H - The stale timer pointer is used in paths that take locks and manipulate lists/callback-related state, making kernel heap corruption and control-flow-impacting exploitation defensible.\nA:H - At minimum, dereferencing and locking a freed kernel timer object can trigger a kernel oops, panic, or hang." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "sound/core/timer.c" ], "versions": [ { "version": "37745918e0e7575bc40f38da93a99b9fa6406224", "lessThan": "586b219a22b1032b28b8bd356b963276c5e5bf53", "status": "affected", "versionType": "git" }, { "version": "37745918e0e7575bc40f38da93a99b9fa6406224", "lessThan": "f46093dd22969037beb1fce2e043f3236be41c92", "status": "affected", "versionType": "git" }, { "version": "37745918e0e7575bc40f38da93a99b9fa6406224", "lessThan": "60e73ab87b84bbd6bd7ddd1d16019a3a3705ab8f", "status": "affected", "versionType": "git" }, { "version": "37745918e0e7575bc40f38da93a99b9fa6406224", "lessThan": "da3039e91d1f835874ed6e9a33ea19ee80c2cb92", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "sound/core/timer.c" ], "versions": [ { "version": "6.12", "status": "affected" }, { "version": "0", "lessThan": "6.12", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.94", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.36", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0.13", "lessThanOrEqual": "7.0.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12", "versionEndExcluding": "6.12.94" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12", "versionEndExcluding": "6.18.36" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12", "versionEndExcluding": "7.0.13" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12", "versionEndExcluding": "7.1" } ] } ] } ], "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" } ], "title": "ALSA: timer: Forcibly close timer instances at closing", "x_generator": { "engine": "bippy-1.2.0" } } } }