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ALSA: timer: drain a slave's callback before its master detaches it

Type: advisorySource: Official CVE List1 source record

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.

Announced Source revision 1
Original source ↗

CVE-2026-68201

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-68201

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "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"
      }
    ],
    "programFiles": [
      "sound/core/timer.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "6.12"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "6.12",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.12.101",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.42",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.1.6",
        "versionType": "semver",
        "lessThanOrEqual": "7.1.*"
      },
      {
        "status": "unaffected",
        "version": "7.2",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "sound/core/timer.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-68201

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#41157 · Revision 1
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Publisher date
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