GHSA-426X-JC5H-FMGG

Vulnerability from github – Published: 2026-04-24 15:32 – Updated: 2026-04-24 15:32
VLAI?
Details

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

ALSA: ctxfi: Limit PTP to a single page

Commit 391e69143d0a increased CT_PTP_NUM from 1 to 4 to support 256 playback streams, but the additional pages are not used by the card correctly. The CT20K2 hardware already has multiple VMEM_PTPAL registers, but using them separately would require refactoring the entire virtual memory allocation logic.

ct_vm_map() always uses PTEs in vm->ptp[0].area regardless of CT_PTP_NUM. On AMD64 systems, a single PTP covers 512 PTEs (2M). When aggregate memory allocations exceed this limit, ct_vm_map() tries to access beyond the allocated space and causes a page fault:

BUG: unable to handle page fault for address: ffffd4ae8a10a000 Oops: Oops: 0002 [#1] SMP PTI RIP: 0010:ct_vm_map+0x17c/0x280 [snd_ctxfi] Call Trace: atc_pcm_playback_prepare+0x225/0x3b0 ct_pcm_playback_prepare+0x38/0x60 snd_pcm_do_prepare+0x2f/0x50 snd_pcm_action_single+0x36/0x90 snd_pcm_action_nonatomic+0xbf/0xd0 snd_pcm_ioctl+0x28/0x40 __x64_sys_ioctl+0x97/0xe0 do_syscall_64+0x81/0x610 entry_SYSCALL_64_after_hwframe+0x76/0x7e

Revert CT_PTP_NUM to 1. The 256 SRC_RESOURCE_NUM and playback_count remain unchanged.

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2026-31602"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-04-24T15:16:39Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: ctxfi: Limit PTP to a single page\n\nCommit 391e69143d0a increased CT_PTP_NUM from 1 to 4 to support 256\nplayback streams, but the additional pages are not used by the card\ncorrectly. The CT20K2 hardware already has multiple VMEM_PTPAL\nregisters, but using them separately would require refactoring the\nentire virtual memory allocation logic.\n\nct_vm_map() always uses PTEs in vm-\u003eptp[0].area regardless of\nCT_PTP_NUM. On AMD64 systems, a single PTP covers 512 PTEs (2M). When\naggregate memory allocations exceed this limit, ct_vm_map() tries to\naccess beyond the allocated space and causes a page fault:\n\n  BUG: unable to handle page fault for address: ffffd4ae8a10a000\n  Oops: Oops: 0002 [#1] SMP PTI\n  RIP: 0010:ct_vm_map+0x17c/0x280 [snd_ctxfi]\n  Call Trace:\n  atc_pcm_playback_prepare+0x225/0x3b0\n  ct_pcm_playback_prepare+0x38/0x60\n  snd_pcm_do_prepare+0x2f/0x50\n  snd_pcm_action_single+0x36/0x90\n  snd_pcm_action_nonatomic+0xbf/0xd0\n  snd_pcm_ioctl+0x28/0x40\n  __x64_sys_ioctl+0x97/0xe0\n  do_syscall_64+0x81/0x610\n  entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nRevert CT_PTP_NUM to 1. The 256 SRC_RESOURCE_NUM and playback_count\nremain unchanged.",
  "id": "GHSA-426x-jc5h-fmgg",
  "modified": "2026-04-24T15:32:35Z",
  "published": "2026-04-24T15:32:35Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31602"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/365c36e1a126c6aa1aecedd3a351bcabc66f0c29"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3fd0685d7fef68c2d8a04876bcf9eaa0724ad6a5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ad9011a795407093dcf507f6e5da1828987b4b47"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b7f5ecd13cce8c2f8fa5a84c9aab65997142577e"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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