GHSA-HXW4-9M57-PRF4

Vulnerability from github – Published: 2026-09-16 12:30 – Updated: 2026-10-30 15:33
VLAI
Details

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

ftrace: Take trace_array reference before accessing its ftrace_ops

The trace instance files set_ftrace_filter and set_ftrace_notrace was updated to work with specific trace instances (trace_arrays). The issue is that when these files are opened, there is a small race window where it will use the ftrace_ops from the inode->private pointer to get a reference to the trace_array and then take its reference. The problem is that the ftrace_ops itself could be freed. If the rmdir on the instance happens at the same time the set_ftrace_filter file is opened, the rmdir could have also freed the ftrace_ops and referencing it will cause a use-after-free bug and crash the kernel.

Instead, pass in the trace_array as the file private data (NULL for the top level instance), and then pass both the trace_array and the ftrace_ops to the ftrace_regex_open() function. If the trace_array is NULL, then it just uses the ftrace_ops without the need to take its reference (like normal). If the ftrace_ops is NULL, that is only the case for the top level instance and the global_ops can be used.

This allows the trace_array to have its reference incremented before touching the ftrace_ops that could also be freed when the instance is.

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-2026-90002"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-16T11:17:12Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nftrace: Take trace_array reference before accessing its ftrace_ops\n\nThe trace instance files set_ftrace_filter and set_ftrace_notrace was\nupdated to work with specific trace instances (trace_arrays). The issue is\nthat when these files are opened, there is a small race window where it\nwill use the ftrace_ops from the inode-\u003eprivate pointer to get a reference\nto the trace_array and then take its reference. The problem is that the\nftrace_ops itself could be freed. If the rmdir on the instance happens at\nthe same time the set_ftrace_filter file is opened, the rmdir could have\nalso freed the ftrace_ops and referencing it will cause a use-after-free\nbug and crash the kernel.\n\nInstead, pass in the trace_array as the file private data (NULL for the\ntop level instance), and then pass both the trace_array and the ftrace_ops\nto the ftrace_regex_open() function. If the trace_array is NULL, then it\njust uses the ftrace_ops without the need to take its reference (like\nnormal). If the ftrace_ops is NULL, that is only the case for the top\nlevel instance and the global_ops can be used.\n\nThis allows the trace_array to have its reference incremented before\ntouching the ftrace_ops that could also be freed when the instance is.",
  "id": "GHSA-hxw4-9m57-prf4",
  "modified": "2026-10-30T15:33:30Z",
  "published": "2026-09-16T12:30:44Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-90002"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0124b36a7eac1dd0402146fc6c1f732877b9cd9f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/177cd8966325f0ffffa3c9381f9e0422019a3973"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/29266da8ee1d9be656b1f22460c49538e1930658"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/83fd7eca5ab0d3ac3f23bff889175d847e21af06"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8f062a6bfeb4b4e18d469a673aec23a7b73c3e8a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9100191e5acb2e5ea2313f436667bb5fce129f47"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cee8f286794df916553d8d445eac5c323ec5b0f8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ffe16fe221e25cd1915602e6753c3d3285ed9a98"
    }
  ],
  "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.