GHSA-44FH-C439-XQ8F

Vulnerability from github – Published: 2026-06-24 18:32 – Updated: 2026-06-30 03:37
VLAI
Details

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

bpf: fix mm lifecycle in open-coded task_vma iterator

The open-coded task_vma iterator reads task->mm locklessly and acquires mmap_read_trylock() but never calls mmget(). If the task exits concurrently, the mm_struct can be freed as it is not SLAB_TYPESAFE_BY_RCU, resulting in a use-after-free.

Safely read task->mm with a trylock on alloc_lock and acquire an mm reference. Drop the reference via bpf_iter_mmput_async() in _destroy() and error paths. bpf_iter_mmput_async() is a local wrapper around mmput_async() with a fallback to mmput() on !CONFIG_MMU.

Reject irqs-disabled contexts (including NMI) up front. Operations used by _next() and _destroy() (mmap_read_unlock, bpf_iter_mmput_async) take spinlocks with IRQs disabled (pool->lock, pi_lock). Running from NMI or from a tracepoint that fires with those locks held could deadlock.

A trylock on alloc_lock is used instead of the blocking task_lock() (get_task_mm) to avoid a deadlock when a softirq BPF program iterates a task that already holds its alloc_lock on the same CPU.

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-2026-53085"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-825"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-24T17:17:22Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: fix mm lifecycle in open-coded task_vma iterator\n\nThe open-coded task_vma iterator reads task-\u003emm locklessly and acquires\nmmap_read_trylock() but never calls mmget(). If the task exits\nconcurrently, the mm_struct can be freed as it is not\nSLAB_TYPESAFE_BY_RCU, resulting in a use-after-free.\n\nSafely read task-\u003emm with a trylock on alloc_lock and acquire an mm\nreference. Drop the reference via bpf_iter_mmput_async() in _destroy()\nand error paths. bpf_iter_mmput_async() is a local wrapper around\nmmput_async() with a fallback to mmput() on !CONFIG_MMU.\n\nReject irqs-disabled contexts (including NMI) up front. Operations used\nby _next() and _destroy() (mmap_read_unlock, bpf_iter_mmput_async)\ntake spinlocks with IRQs disabled (pool-\u003elock, pi_lock). Running from\nNMI or from a tracepoint that fires with those locks held could\ndeadlock.\n\nA trylock on alloc_lock is used instead of the blocking task_lock()\n(get_task_mm) to avoid a deadlock when a softirq BPF program iterates\na task that already holds its alloc_lock on the same CPU.",
  "id": "GHSA-44fh-c439-xq8f",
  "modified": "2026-06-30T03:37:13Z",
  "published": "2026-06-24T18:32:46Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53085"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/security/cve/CVE-2026-53085"
    },
    {
      "type": "WEB",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2492404"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/239cec25a22662dbd80f57d94b38178c8be95269"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/43683bb280330f3d36f0f2a3932a4867b9603e9c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d0862de7c866c5bd7c32531f66738c21197af888"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d8e27d2d22b6e2df3a0125b8c08e9aace38c954c"
    },
    {
      "type": "WEB",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53085.json"
    }
  ],
  "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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