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CVE-2026-53193

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: ALSA: timer: Forcibly close timer instances at closing When snd_timer object is freed via snd_timer_free() and still pending snd_timer_instance objects are assigned to the timer object, it tries to unlink all instances and just set NULL to each ti->timer, then releases the resources immediately. The problem is, however, when there are slave timer instances that are associated with a master instance linked to this timer: namely, those slave instances still point to the freed timer object although the master instance is unlinked, which may lead to user-after-free. The bug can be easily triggered particularly when a new userspace-driven timers (CONFIG_SND_UTIMER) is involved, since it can create and delete the timer object via a simple file open/close, while the other applications may keep accessing to that timer. This patch is an attempt to paper over the problem above: now instead of just unlinking, call snd_timer_close[_locked]() forcibly for each pending timer instance, so that all assigned slave timer instances are properly detached, too. Since snd_timer_close() might be called later by the driver that created that instance, the check of SNDRV_TIMER_IFLG_DEAD is added at the beginning, too.

Severity
HIGH
CVSS score
7.8 (v3.1)
Vulnerability status
Modified
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-06-25 09:16:36.757000
Last modified
2026-10-19 20:19:08.330000
View original CVE JSON 
{
  "id": "CVE-2026-53193",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-06-25T09:16:36.757",
  "lastModified": "2026-10-19T20:19:08.330",
  "vulnStatus": "Modified",
  "cveTags": [],
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    {
      "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."
    }
  ],
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          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
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