{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "586b219a22b1032b28b8bd356b963276c5e5bf53"
            },
            {
              "fixed": "bb016091010ec401a06e6bdace0cd944ee03d371"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "f46093dd22969037beb1fce2e043f3236be41c92"
            },
            {
              "fixed": "a26a2e52736f9e39843ca66a2e1ce6bf1adbcd1e"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "da3039e91d1f835874ed6e9a33ea19ee80c2cb92"
            },
            {
              "fixed": "0c561fab50991df10b1e4daca25886c34a2a9c07"
            },
            {
              "fixed": "c2744d5f3aea474513fd2298daecb94a952ce441"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "60e73ab87b84bbd6bd7ddd1d16019a3a3705ab8f"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "6.12.94"
            },
            {
              "fixed": "6.12.103"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "6.18.36"
            },
            {
              "fixed": "6.18.44"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "7.0.13"
            },
            {
              "fixed": "7.1"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.12.103"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.44"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.1.8"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74503.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: timer: Clear SNDRV_TIMER_IFLG_DEAD once the close completes\n\nsnd_timer_close_locked() marks an instance with SNDRV_TIMER_IFLG_DEAD\nand returns early when the flag is already set, but the flag is never\ncleared again.  A completed close ends in remove_slave_links(), which\nleaves timeri-\u003etimer NULL, so a second close is already harmless through\nthe timer == NULL path; the early return can only be reached by an\ninstance that was opened again in between.  For such an instance the\nclose unlinks nothing, so snd_timer_instance_free() frees an object that\nis still on timer-\u003eopen_list_head, still on snd_timer_master_list if it\nwas opened with a slave key, still owns any adopted slaves, and still\nholds its timer and module references.\n\nsnd_seq_timer_open() reopens an instance exactly like that: it retries\nits fallback open on the same object after a failure that has already\nrun snd_timer_close_locked() internally.  An unprivileged user with\naccess to /dev/snd/timer and /dev/snd/seq can force that failure, since\nsnd_timer_check_master() returns -EBUSY when a pending slave matches the\nnew master's (slave_class, slave_id) key and the target timer has\nreached max_instances, and SNDRV_TIMER_IOCTL_SELECT with dev_class =\nSNDRV_TIMER_CLASS_SLAVE keeps the caller-supplied dev_sclass, so a\nsequencer queue's key can be forged.  The freed instance is afterwards\ndereferenced by any further snd_timer_open() on that timer, by\nsnd_timer_check_slave(), and by /proc/asound/timers, which faults on the\nstale ti-\u003eowner pointer.\n\nThe flag only has to be visible while the close is in progress, which is\nall its other users need.  Clear it in remove_slave_links(), under the\nsame timer-\u003elock that sets it, once the instance is off every list.",
  "id": "CVE-2026-74503",
  "modified": "2026-08-17T03:36:09.301835685Z",
  "published": "2026-08-15T12:27:28.208Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0c561fab50991df10b1e4daca25886c34a2a9c07"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a26a2e52736f9e39843ca66a2e1ce6bf1adbcd1e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bb016091010ec401a06e6bdace0cd944ee03d371"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c2744d5f3aea474513fd2298daecb94a952ce441"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74503.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74503"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "ALSA: timer: Clear SNDRV_TIMER_IFLG_DEAD once the close completes"
}