GHSA-QF88-XW8W-824G

Vulnerability from github – Published: 2026-07-19 18:31 – Updated: 2026-07-20 15:31
VLAI
Details

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

batman-adv: tp_meter: directly shut down timer on cleanup

batadv_tp_sender_cleanup() was calling timer_delete_sync() followed by timer_delete() to guard against the timer handler re-arming itself between the two calls. This double-deletion hack relied on the sending status being set to 0 to suppress re-arming.

Replace both calls with a single timer_shutdown_sync(). This function both waits for any running timer callback to complete (like timer_delete_sync()) and permanently disarms the timer so it cannot be re-armed afterwards, making re-arming prevention unconditional and self-documenting.

The re-arming property is also required because otherwise:

  1. context 0 (batadv_tp_recv_ack()) checks in batadv_tp_reset_sender_timer() if sending is still 1 -> it is
  2. context 1 changes in batadv_tp_sender_shutdown() sending to 0 and in this process forces the kthread to stop timer in batadv_tp_sender_cleanup()
  3. context 0 continues in batadv_tp_reset_sender_timer() and rearms the timer -> but the reference for it is already gone
Severity
8.8 (High)
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2026-64093"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-19T16:17:50Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbatman-adv: tp_meter: directly shut down timer on cleanup\n\nbatadv_tp_sender_cleanup() was calling timer_delete_sync() followed by\ntimer_delete() to guard against the timer handler re-arming itself between\nthe two calls. This double-deletion hack relied on the sending status being\nset to 0 to suppress re-arming.\n\nReplace both calls with a single timer_shutdown_sync(). This function both\nwaits for any running timer callback to complete (like timer_delete_sync())\nand permanently disarms the timer so it cannot be re-armed afterwards,\nmaking re-arming prevention unconditional and self-documenting.\n\nThe re-arming property is also required because otherwise:\n\n1. context 0 (batadv_tp_recv_ack()) checks in\n   batadv_tp_reset_sender_timer() if sending is still 1 -\u003e it is\n2. context 1 changes in batadv_tp_sender_shutdown() sending to 0 and in\n   this process forces the kthread to stop timer in\n   batadv_tp_sender_cleanup()\n3. context 0 continues in batadv_tp_reset_sender_timer() and rearms the\n   timer -\u003e but the reference for it is already gone",
  "id": "GHSA-qf88-xw8w-824g",
  "modified": "2026-07-20T15:31:59Z",
  "published": "2026-07-19T18:31:51Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64093"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/00bf4bb9947b1190a8be8d9b6a1bcbfa3707785c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5bc2d50fb66b46f86543d5153a188eb1486d0b6e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/74a76634055462833446684fd526d73c290ea43a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/770bf0a35f0620b526fd4193889d1e77084e4c43"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/933880a8bc9b4042223a79255c0b1021cdc36991"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d5487249a81ea658717614009c8f46acc5b7101a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f86b20ec8d17d77bddc02c5c86cfa2389d84ecff"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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