GHSA-R2RW-736Q-8CV3

Vulnerability from github – Published: 2026-09-16 12:30 – Updated: 2026-09-16 15:31
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

ALSA: pcm: Fix race between non-atomic ops and trigger-start

We protect the races of the concurrent state transitions between atomic PCM ops, but the checks between the non-atomic ops (hw_params, hw_free and prepare) and the atomic ops aren't perfect; there is a check of the conflicting PCM state at the beginning of hw_params & co, but the atomic PCM ops can be still issued during the non-atomic PCM operations. An example such scenario is that a thread A re-issues the PREPARE or HW_PARAMS for the already prepared stream, while another thread B triggers the PCM start in the middle of the prepare operation. Although this usually doesn't lead to much serious issues, it can give some inconsistency as reported by syzkaller (such as ODEBUG warning).

There are various atomic PCM ops, and basically the only problem is the PCM start as it operates from the PREPARED state. Other trigger commands (stop, etc) are for the running or the other special state, hence they are filtered as pre-condition.

This patch is for preventing the PCM trigger-start during the non- atomic operations in order to address the problems above. Fortunately, the hw_params, hw_free and prepare operations call snd_pcm_buffer_access_lock(), and this can be used for checking the concurrent operations at the PCM trigger -- which sets the runtime->buffer_accessing to a negative (if possible), so the PCM trigger just needs to check the runtime->buffer_accessing value; if it's negative, it means the concurrent non-atomic PCM ops is running.

Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2026-89979"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-16T11:17:08Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: pcm: Fix race between non-atomic ops and trigger-start\n\nWe protect the races of the concurrent state transitions between\natomic PCM ops, but the checks between the non-atomic ops (hw_params,\nhw_free and prepare) and the atomic ops aren\u0027t perfect; there is a\ncheck of the conflicting PCM state at the beginning of hw_params \u0026 co,\nbut the atomic PCM ops can be still issued during the non-atomic PCM\noperations.  An example such scenario is that a thread A re-issues the\nPREPARE or HW_PARAMS for the already prepared stream, while another\nthread B triggers the PCM start in the middle of the prepare\noperation.  Although this usually doesn\u0027t lead to much serious issues,\nit can give some inconsistency as reported by syzkaller (such as\nODEBUG warning).\n\nThere are various atomic PCM ops, and basically the only problem is\nthe PCM start as it operates from the PREPARED state.  Other trigger\ncommands (stop, etc) are for the running or the other special state,\nhence they are filtered as pre-condition.\n\nThis patch is for preventing the PCM trigger-start during the non-\natomic operations in order to address the problems above.\nFortunately, the hw_params, hw_free and prepare operations call\nsnd_pcm_buffer_access_lock(), and this can be used for checking the\nconcurrent operations at the PCM trigger -- which sets the\nruntime-\u003ebuffer_accessing to a negative (if possible), so the PCM\ntrigger just needs to check the runtime-\u003ebuffer_accessing value; if\nit\u0027s negative, it means the concurrent non-atomic PCM ops is running.",
  "id": "GHSA-r2rw-736q-8cv3",
  "modified": "2026-09-16T15:31:04Z",
  "published": "2026-09-16T12:30:44Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89979"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/50afadf1ea66597116eb14e73c24da7ae99b759f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5abeb4f9f2023f001d693b4e5e1ebbf25e25d0eb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7ad2ea7c10044b08ecf7b04376916faf12e17a99"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/acac7b5e07349a9d10d78873afb4b93cd1dc721f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ad29779736cfd6f5595f0cab300dd7611418e363"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b1d12144557fceed5de6e22e2c2e30a40ed37702"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b2edc017f94c08bdd0b046a586e43ac771a2f942"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b599e7f16441386754ec083fa62a549bccb02fca"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

JSON
How durations are calculated

Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

Loading timeline…




    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.