CVE-2026-68201

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: ALSA: timer: drain a slave's callback before its master detaches it snd_timer_close_locked() drains the closing instance's own in-flight callback (IFLG_CALLBACK) before freeing it, but not its slaves'. When a master instance is closed, remove_slave_links() clears each slave's ->timer; the slave's own close then reads timer == NULL and takes the branch that skips the drain entirely (snd_timer_stop_slave() also no-ops on a NULL timer). So a slave whose callback is still running when the master is closed is freed underneath the live callback, leading to use-after-free. Drain the slaves too before remove_slave_links() severs them. snd_timer_stop() has already taken this instance off the active list, so no new slave callback can be queued. Take the slaves off the ack list so a pending one can't fire either, then wait for any that is already in flight.

Severity

HIGH

CVSS score

7.8 (v3.1)

Vulnerability status

Received

Source identifier

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Published

2026-08-10 13:20:07.647000

Last modified

2026-10-19 21:17:57.940000

View original CVE JSON

{
  "id": "CVE-2026-68201",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-08-10T13:20:07.647",
  "lastModified": "2026-10-19T21:17:57.940",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: timer: drain a slave's callback before its master detaches it\n\nsnd_timer_close_locked() drains the closing instance's own in-flight\ncallback (IFLG_CALLBACK) before freeing it, but not its slaves'. When a\nmaster instance is closed, remove_slave_links() clears each slave's\n->timer; the slave's own close then reads timer == NULL and takes the\nbranch that skips the drain entirely (snd_timer_stop_slave() also no-ops\non a NULL timer). So a slave whose callback is still running when the\nmaster is closed is freed underneath the live callback, leading to\nuse-after-free.\n\nDrain the slaves too before remove_slave_links() severs them.\nsnd_timer_stop() has already taken this instance off the active list, so\nno new slave callback can be queued. Take the slaves off the ack list so\na pending one can't fire either, then wait for any that is already in\nflight."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "sound/core/timer.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "37745918e0e7575bc40f38da93a99b9fa6406224",
              "lessThan": "cd461bcfcdf8d6b6b5365941c1d3859f8bc77aa0",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "37745918e0e7575bc40f38da93a99b9fa6406224",
              "lessThan": "426c0ff1c433d6030610ad4f9375746dfe931caa",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "37745918e0e7575bc40f38da93a99b9fa6406224",
              "lessThan": "2b298997786876b225cff2446e11a0fa6f602f6d",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "37745918e0e7575bc40f38da93a99b9fa6406224",
              "lessThan": "bdefe1346a8e6b8dc8593406dc2617e985fcbcab",
              "versionType": "git",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "sound/core/timer.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "6.12",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "6.12",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.12.101",
              "lessThanOrEqual": "6.12.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.18.42",
              "lessThanOrEqual": "6.18.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.1.6",
              "lessThanOrEqual": "7.1.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.2",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary",
        "cvssData": {
          "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",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-10-16T15:45:48.460607Z",
          "id": "CVE-2026-68201",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-416"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/2b298997786876b225cff2446e11a0fa6f602f6d",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/426c0ff1c433d6030610ad4f9375746dfe931caa",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/bdefe1346a8e6b8dc8593406dc2617e985fcbcab",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/cd461bcfcdf8d6b6b5365941c1d3859f8bc77aa0",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ]
}