GHSA-27J8-6Q5H-M6JX

Vulnerability from github – Published: 2026-05-08 15:31 – Updated: 2026-05-21 18:33
VLAI
Details

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

serial: caif: hold tty->link reference in ldisc_open and ser_release

A reproducer triggers a KASAN slab-use-after-free in pty_write_room() when caif_serial's TX path calls tty_write_room(). The faulting access is on tty->link->port.

Hold an extra kref on tty->link for the lifetime of the caif_serial line discipline: get it in ldisc_open() and drop it in ser_release(), and also drop it on the ldisc_open() error path.

With this change applied, the reproducer no longer triggers the UAF in my testing.

Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2026-43458"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-416"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-05-08T15:16:58Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nserial: caif: hold tty-\u003elink reference in ldisc_open and ser_release\n\nA reproducer triggers a KASAN slab-use-after-free in pty_write_room()\nwhen caif_serial\u0027s TX path calls tty_write_room(). The faulting access\nis on tty-\u003elink-\u003eport.\n\nHold an extra kref on tty-\u003elink for the lifetime of the caif_serial line\ndiscipline: get it in ldisc_open() and drop it in ser_release(), and\nalso drop it on the ldisc_open() error path.\n\nWith this change applied, the reproducer no longer triggers the UAF in\nmy testing.",
  "id": "GHSA-27j8-6q5h-m6jx",
  "modified": "2026-05-21T18:33:06Z",
  "published": "2026-05-08T15:31:29Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-43458"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/23a3ac2e2262a291498567418227b99e1f3606b1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/27e43356d0defb9fc7fa25265219a3ffeb7b3e98"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/288598d80a068a0e9281de35bcb4ce495f189e2a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/35b58d3bc716ebb9ebd10fe1cac8c1177242511c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/52135420e9f75853ea0c6cea7b736e3e98495f7d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8460187b4852fd00bd1c76394358053f3fa4d089"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/97a0bb491cae39478c6225381f14e9ac67b7bba7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ca2ceba983bb23ea0202c2882d963253416654a3"
    }
  ],
  "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"
    }
  ]
}


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