GHSA-JVRV-JPH4-C9C9

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:

mm/vmalloc: do not trigger BUG() on BH disabled context

__get_vm_area_node() currently triggers a BUG() if in_interrupt() returns true. However, in_interrupt() also reports true when BH are disabled.

The bridge code can call rhashtable_lookup_insert_fast() with bottom halves disabled:

__vlan_add() -> br_fdb_add_local() spin_lock_bh(&br->hash_lock); <-- Disable BH -> fdb_add_local() -> fdb_create() -> rhashtable_lookup_insert_fast() -> kvmalloc() -> vmalloc() -> __get_vm_area_node() -> BUG_ON(in_interrupt()) spin_unlock_bh(&br->hash_lock)

this triggers the BUG() despite the caller not being in NMI or hard IRQ context.

Replace the in_interrupt() check with in_nmi() || in_hardirq().

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2026-63955"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-19T16:17:14Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/vmalloc: do not trigger BUG() on BH disabled context\n\n__get_vm_area_node() currently triggers a BUG() if in_interrupt() returns\ntrue.  However, in_interrupt() also reports true when BH are disabled.\n\nThe bridge code can call rhashtable_lookup_insert_fast() with bottom\nhalves disabled:\n\n__vlan_add()\n -\u003e br_fdb_add_local()\n  spin_lock_bh(\u0026br-\u003ehash_lock); \u003c-- Disable BH\n   -\u003e fdb_add_local()\n    -\u003e fdb_create()\n     -\u003e rhashtable_lookup_insert_fast()\n      -\u003e kvmalloc()\n       -\u003e vmalloc()\n        -\u003e __get_vm_area_node()\n         -\u003e BUG_ON(in_interrupt())\n  spin_unlock_bh(\u0026br-\u003ehash_lock)\n\nthis triggers the BUG() despite the caller not being in NMI or\nhard IRQ context.\n\nReplace the in_interrupt() check with in_nmi() || in_hardirq().",
  "id": "GHSA-jvrv-jph4-c9c9",
  "modified": "2026-07-20T15:31:53Z",
  "published": "2026-07-19T18:31:47Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-63955"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/04aa71da5f35aacdc9ae9cb5150947daa624f641"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ad7eff07b625f53c3fb513b30d7a8c5a79fbc7ce"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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